Albumin variants

ABSTRACT

The present invention relates to variants of a parent albumin, the variants having altered plasma half-life compared with the parent albumin. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 14/685,112, filed on Apr. 13, 2015, which is a divisional of U.S. patent application Ser. No. 14/075,104 filed Nov. 8, 2013, pending, which claims priority or the benefit under 35 U.S.C. 119 of European Application No. 12191856.9 filed Nov. 8, 2012 and U.S. Provisional Application No. 61/724,669 filed Nov. 9, 2012, the contents of which are fully incorporated herein by reference.

REFERENCE TO SEQUENCE LISTING

This application contains a Sequence Listing in computer readable form, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to variants of albumin or fragments thereof or fusion polypeptides comprising variant albumin or fragments thereof having a change in binding affinity to FcRn and/or a change in half-life compared to the albumin, fragment thereof or fusion polypeptide comprising albumin or a fragment thereof. The invention allows tailoring of binding affinity and/or half-life of an albumin to the requirements and desires of a user or application.

Description of the Related Art

Albumin is a protein naturally found in the blood plasma of mammals where it is the most abundant protein. It has important roles in maintaining the desired osmotic pressure of the blood and also in transport of various substances in the blood stream. Albumins have been characterized from many species including human, pig, mouse, rat, rabbit and goat and they share a high degree of sequence and structural homology.

Albumin binds in vivo to its receptor, the neonatal Fc receptor (FcRn) “Brambell” and this interaction is known to be important for the plasma half-life of albumin. FcRn is a membrane bound protein, expressed in many cell and tissue types. FcRn has been found to salvage albumin from intracellular degradation (Roopenian D. C. and Akilesh, S. (2007), Nat. Rev. Immunol 7, 715-725.). FcRn is a bifunctional molecule that contributes to maintaining a high level of IgGs and albumin in serum in mammals such as human beings.

Whilst the FcRn-immunoglobulin (IgG) interaction has been characterized in the prior art, the FcRn-albumin interaction is less well characterized. The major FcRn binding site is localized within DIII (381-585), (Andersen et al (2010), Clinical Biochemistry 43, 367-372). A number of key amino acids have been shown to be important in binding, notably histidines H464, H510 and H536 and Lys500 (Andersen et al (2010), Nat. Commun. 3:610. DOI:10.1038/ncomms1607). The crystal structure of a human serum albumin (HSA) variant (V418M+T420A+E505G+V547A) with strong affinity to FcRn at acidic pH and in addition with increased binding at neutral pH has been reported allowing more detailed understanding of the interacting interfaces. In addition, the authors were able to alter the affinity to FcRn through amino acid substitution and show that this could translate into increased circulatory half-lives in mice and monkey, most notably for HSA E505G+V547A (Schmidt et al (2012), Cell Structure. 21, Issue 11, (doi:10.1016/j.str.2013.08.022)).

Data indicates that IgG and albumin bind non-cooperatively to distinct sites on FcRn (Andersen et al. (2006), Eur. J. Immunol 36, 3044-3051; Chaudhury et al. (2006), Biochemistry 45, 4983-4990).

It is known that mouse FcRn binds IgG from mice and humans whereas human FcRn appears to be more discriminating (Ober et al. (2001) Int. Immunol 13, 1551-1559). Andersen et al. (2010) Journal of Biological Chemistry 285(7):4826-36, describes the affinity of human and mouse FcRn for each mouse and human albumin (all possible combinations). No binding of albumin from either species was observed at physiological pH to either receptor. At acidic pH, a 100-fold difference in binding affinity was observed. In all cases, binding of albumin and IgG from either species to both receptors were additive.

Human serum albumin (HSA) has been well characterized as a polypeptide of 585 amino acids, the sequence of which can be found in Peters, T., Jr. (1996) All about Albumin: Biochemistry, Genetics and Medical, Applications pp 10, Academic Press, Inc., Orlando (ISBN 0-12-552110-3). It has a characteristic binding to its receptor FcRn, where it binds at pH 6.0 but not at pH 7.4.

The plasma half-life of HSA has been found to be approximately 19 days. A natural variant having lower plasma half-life has been identified (Peach, R. J. and Brennan, S. 0., (1991) Biochim Biophys Acta. 1097:49-54) having the substitution D494N. This substitution generated an N-glycosylation site in this variant, which is not present in the wild-type albumin. It is not known whether the glycosylation or the amino acid change is responsible for the change in plasma half-life.

Albumin has a long plasma half-life and because of this property it has been suggested for use in drug delivery. Albumin has been conjugated to pharmaceutically beneficial compounds (WO2000/69902), and it was found that the conjugate maintained the long plasma half-life of albumin. The resulting plasma half-life of the conjugate was generally considerably longer than the plasma half-life of the beneficial therapeutic compound alone.

Further, albumin has been genetically fused to therapeutically beneficial peptides (WO 2001/79271 A and WO2003/59934) with the typical result that the fusion has the activity of the therapeutically beneficial peptide and a considerably longer plasma half-life than the plasma half-life of the therapeutically beneficial peptides alone.

Otagiri et al (2009), Biol. Pharm. Bull. 32(4), 527-534, discloses more than 70 albumin variants, of these 25 of these are found to be mutated in domain III. A natural variant lacking the last 175 amino acids at the carboxy termini has been shown to have reduced half-life (Andersen et al (2010), Clinical Biochemistry 43, 367-372). Iwao et al (2007) studied the half-life of naturally occurring human albumin variants using a mouse model, and found that K541E and K560E had reduced half-life, E501K and E570K had increased half-life and K573E had almost no effect on half-life (Iwao, et. al. (2007) B.B.A. Proteins and Proteomics 1774, 1582-1590).

Galliano et al (1993) Biochim. Biophys. Acta 1225, 27-32 discloses a natural variant E505K. Minchiotti et al (1990) discloses a natural variant K536E. Minchiotti et al (1987) Biochim. Biophys. Acta 916, 411-418, discloses a natural variant K574N. Takahashi et al (1987) Proc. Natl. Acad. Sci. USA 84, 4413-4417, discloses a natural variant D550G. Carlson et al (1992). Proc. Nat. Acad. Sci. USA 89, 8225-8229, discloses a natural variant D550A.

WO2011/051489 and WO2012/150319 disclose a number of point mutations in albumin which modulate the binding of albumin to FcRn. WO2010/092135 discloses a number of point mutations in albumin which increase the number of thiols available for conjugation in the albumin, the disclosure is silent about the affect of the mutations on the binding of the albumin to FcRn. WO2011/103076 discloses albumin variants, each containing a substitution in Domain III of HSA. WO2012/112188 discloses albumin variants containing substitutions in Domain III of HSA.

Albumin has the ability to bind a number of ligands and these become associated (associates) with albumin. This property has been utilized to extend the plasma half-life of drugs having the ability to non-covalently bind to albumin. This can also be achieved by binding a pharmaceutical beneficial compound, which has little or no albumin binding properties, to a moiety having albumin binding properties, see review article and reference therein, Kratz (2008) Journal of Controlled Release 132, 171-183.

Albumin is used in preparations of pharmaceutically beneficial compounds, in which such a preparation may be for example, but not limited to, a nanoparticle or microparticle of albumin. In these examples the delivery of a pharmaceutically beneficial compound or mixture of compounds may benefit from alteration in the albumin's affinity to its receptor where the beneficial compound has been shown to associate with albumin for the means of delivery. It is not clear what determines the plasma half-life of the formed associates (for example but not limited to Levemir®, Kurtzhals P et al. Biochem. J. 1995; 312:725-731), conjugates or fusion polypeptides but it appears to be a result of the combination of the albumin and the selected pharmaceutically beneficial compound/polypeptide. It would be desirable to be able to control the plasma half-life of given albumin conjugates, associates or albumin fusion polypeptides so that a longer or shorter plasma half-life can be achieved than given by the components of the association, conjugation or fusion, in order to be able to design a particular drug according to the particulars of the indication intended to be treated.

Albumin is known to accumulate and be catabolised in tumours, it has also been shown to accumulate in inflamed joints of rheumatoid arthritis sufferers. See review article and reference therein, Kratz (2008) Journal of Controlled Release 132, 171-183. It is envisaged that HSA variants with increased affinity for FcRn would be advantageous for the delivery of pharmaceutically beneficial compounds.

It may even be desirable to have variants of albumin that have little or no binding to FcRn in order to provide shorter half-lives or controlled serum pharmacokinetics as described by Kenanova et al (2009) J. Nucl. Med.; 50 (Supplement 2):1582). Kenanova et al (2010, Protein Engineering, Design & Selection 23(10): 789-798; WO2010/118169) discloses a docking model comprising a structural model of domain III of HSA (solved at pH 7 to 8) and a structural model of FcRn (solved at pH 6.4). Kenanova et al discloses that positions 464, 505, 510, 531 and 535 in domain III potentially interact with FcRn. The histidines at positions 464, 510 and 535 were identified as being of particular interest by Chaudhury et al., (2006, op. cit.) and these were shown to have a significant reduction in affinity and shorter half-life in mouse by Kenanova (2010, op. cit.). However, the studies of Kenanova et al are limited to domain III of HSA and therefore do not consider HSA in its native intact configuration. Furthermore, the identified positions result in a decrease in affinity for the FcRn receptor.

The present invention provides further variants having altered binding affinity to the FcRn receptor. The albumin moiety or moieties may therefore be used to tailor the binding affinity to FcRn and/or half-life of fusion polypeptides, conjugates, associates, nanoparticles and compositions comprising the albumin moiety.

SUMMARY OF THE INVENTION

The present invention relates to albumin variants comprising an alteration at positions corresponding to positions selected among two or more of the group consisting of positions 492, 550, 573, 574 and 580 of the mature polypeptide of SEQ ID NO: 2 or equivalent positions of other albumins or fragments thereof. Position 492 is located in the connector loop between subdomain DIIIa and subdomain DIIIb. Positions 550, 573, 574 and 580 are located in subdomain DIIIb. Subdomain IIIb is located proximal to the connector loop between subdomain DIIIa and subdomain DIIIb.

The present invention also relates to isolated polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of producing the variants.

The invention also relates to conjugates or associates comprising the variant albumin or fragment thereof according to the invention and a beneficial therapeutic moiety or to a fusion polypeptide comprising a variant albumin or fragment thereof of the invention and a fusion partner polypeptide.

The invention further relates to compositions comprising the variant albumin, fragment thereof, fusion polypeptide comprising variant albumin or fragment thereof or conjugates comprising the variant albumin or fragment thereof, according to the invention or associates comprising the variant albumin or fragment thereof, according to the invention. The compositions are preferably pharmaceutical compositions.

The invention further relates to a pharmaceutical composition comprising a variant albumin, fragment thereof, fusion polypeptide comprising variant albumin or fragment thereof or conjugates comprising the variant albumin or fragment thereof, or associates comprising the variant albumin or fragment thereof.

The invention also relates to the use of the variants, fragments, fusion polypeptides, conjugates, associates, nanoparticles and microparticles.

The invention also relates to a method for preparing a variant albumin, fragment thereof, fusion polypeptide comprising variant albumin or fragment thereof or conjugates comprising the variant albumin or fragment thereof, or associates comprising the variant albumin or fragment thereof.

BRIEF DESCRIPTION OF THE FIGURES

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

FIG. 1: Multiple alignment of amino acid sequences of (i) full length mature HSA (Hu_1_2_3) (SEQ ID NO: 2), (ii) an albumin variant comprising domain I and domain III of HSA (Hu_1_3) (SEQ ID NO: 24), (iii) an albumin variant comprising domain II and domain III of HSA (Hu_2_3) (SEQ ID NO: 25), (iv) full-length Macaca mulatta albumin (Mac_mul) (SEQ ID NO: 6), (v) full-length Rattus norvegicus albumin (Rat) (SEQ ID NO: 10) and (vi) full-length Mus musculus albumin (Mouse) (SEQ ID NO: 9). Positions 500, 550 and 573 (relative to full length HSA) are indicated by arrows. In FIG. 1, Domains I, II and III are referred to as 1, 2 and 3 (respectively).

FIG. 2: Multiple alignment of amino acid sequences of mature albumin from human (SEQ ID NO: 2), sheep (SEQ ID NO: 16), mouse (SEQ ID NO: 9), rabbit (SEQ ID NO: 14) and goat (SEQ ID NO: 15) and immature albumins from chimpanzee (“Chimp”) (SEQ ID NO: 5), macaque (SEQ ID NO: 6), hamster (SEQ ID NO: 7), guinea pig (SEQ ID NO: 8), rat (SEQ ID NO: 10), cow (SEQ ID NO: 11), horse (SEQ ID NO: 12), donkey (SEQ ID NO: 13), dog (SEQ ID NO: 17), chicken (SEQ ID NO: 18), and pig (SEQ ID NO: 19). The Start and End amino acids of domains 1, 2 and 3 (as defined by Dockal et al (The Journal of Biological Chemistry, 1999, Vol. 274(41): 29303-29310)) are indicated with respect to mature human albumin.

FIG. 3: Conserved groups of amino acids based on their properties.

FIG. 4: Representation of shFcRn-HSA docking model. (A-B) Two orientations of the complex are shown. Albumin is shown by a space-filling diagram, FcRn is shown as a ribbon diagram. The core binding interface of HSA is highlighted in pink (in grey-scale this is seen as the darkest (almost black) region; DI (CBI)), while the area distally localized from the interface is shown as DII (orange) and DIII is split into sub-domains DIIIa (in colour, this is cyan) and DIIIb (in colour, this is blue).

DEFINITIONS

Variant: The term “variant” means a polypeptide derived from a parent albumin by one or more (several) alteration(s), i.e., a substitution, insertion, and/or deletion, at one or more (several) positions. A substitution means a replacement of an amino acid occupying a position with a different amino acid; a deletion means removal of an amino acid occupying a position; and an insertion means adding 1 or more, such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, preferably 1-3 amino acids immediately adjacent an amino acid occupying a position. In relation to substitutions, ‘immediately adjacent’ may be to the N-side (‘upstream’) or C-side (‘downstream’) of the amino acid occupying a position (‘the named amino acid’). Therefore, for an amino acid named/numbered ‘X’, the insertion may be at position ‘X+1’ (‘downstream’) or at position ‘X−1’ (‘upstream’).

Mutant: The term “mutant” means a polynucleotide encoding a variant.

Wild-Type Albumin: The term “wild-type” (WT) albumin means albumin having the same amino acid sequence as naturally found in an animal or in a human being.

Parent Albumin: The term “parent” or “parent albumin” means an albumin to which an alteration is made by the hand of man to produce the albumin variants of the invention. The parent may be a naturally occurring (wild-type) polypeptide or an allele thereof, or even a variant thereof.

Albumin: Albumins are proteins and constitute the most abundant protein in plasma in mammals and albumins from a long number of mammals have been characterized by biochemical methods and/or by sequence information. Several albumins, e.g., human serum albumin (HSA), have also been characterized crystallographically and the structure determined (HSA: He X M, Carter D C (July 1992). “Atomic structure and chemistry of human serum albumin”. Nature 358 (6383): 209-15; horse albumin: Ho, J. X. et al. (2001). X-ray and primary structure of horse serum albumin (Equus caballus) at 0.27-nm resolution. Eur J Biochem. 215(1):205-12).

The term “albumin” means a protein having the same and/or very similar three dimensional (tertiary) structure as HSA or HSA domains and has similar properties to HSA or to the relevant domains. Similar three dimensional structures are for example the structures of the albumins from the species mentioned herein. Some of the major properties of albumin are i) its ability to regulate plasma volume (oncotic activity), ii) a long plasma half-life of around 19 days±5 days, iii) binding to FcRn, iv) ligand-binding, e.g. binding of endogenous molecules such as acidic, lipophilic compounds including bilirubin, fatty acids, hemin and thyroxine (see also table 1 of Kragh-Hansen et al, 2002, Biol. Pharm. Bull. 25, 695, hereby incorporated by reference), v) binding of small organic compounds with acidic or electronegative features e.g. drugs such as warfarin, diazepam, ibuprofen and paclitaxel (see also table 1 of Kragh-Hansen et al, 2002, Biol. Pharm. Bull. 25, 695, hereby incorporated by reference). Not all of these properties need to be fulfilled in order to characterize a protein or fragment as an albumin. If a fragment, for example, does not comprise a domain responsible for binding of certain ligands or organic compounds the variant of such a fragment will not be expected to have these properties either.

Albumins have generally a long plasma half-life of approximately 20 days or longer, e.g., HSA has a plasma half-life of 19 days. It is known that the long plasma half-life of HSA is mediated via interaction with its receptor FcRn, however, an understanding or knowledge of the exact mechanism behind the long half-life of HSA is not essential for the invention.

As examples of albumin proteins, more specifically albumin proteins which may be used as parent ‘backbones’ as a starting point for making the albumin variants according to the invention, can be mentioned human serum albumin (e.g. AAA98797 or P02768-1, SEQ ID NO: 2 (mature), SEQ ID NO: 4 (immature)), primate serum albumin, (such as chimpanzee serum albumin (e.g. predicted sequence XP_517233.2 SEQ ID NO: 5), gorilla serum albumin or macaque serum albumin (e.g. NP_001182578, SEQ ID NO: 6), rodent serum albumin (such as hamster serum albumin (e.g. A6YF56, SEQ ID NO: 7), guinea pig serum albumin (e.g. Q6WDN9-1, SEQ ID NO: 8), mouse serum albumin (e.g. AAH49971 or P07724-1 Version 3, SEQ ID NO: 9) and rat serum albumin (e.g. AAH85359 or P02770-1 Version 2, SEQ ID NO: 10))), bovine serum albumin (e.g. cow serum albumin P02769-1, SEQ ID NO: 11), equine serum albumin such as horse serum albumin (e.g. P35747-1, SEQ ID NO: 12) or donkey serum albumin (e.g. Q5XLE4-1, SEQ ID NO: 13), rabbit serum albumin (e.g. P49065-1 Version 2, SEQ ID NO: 14), goat serum albumin (e.g. ACF10391, SEQ ID NO: 15), sheep serum albumin (e.g. P14639-1, SEQ ID NO: 16), dog serum albumin (e.g. P49822-1, SEQ ID NO: 17), chicken serum albumin (e.g. P19121-1 Version 2, SEQ ID NO: 18) and pig serum albumin (e.g. P08835-1 Version 2, SEQ ID NO: 19) or a polypeptide having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or at least 99% amino acid identity to such an albumin. The parent or reference albumin may be an artificial variant such as HSA. K573P (SEQ ID NO: 3) or a chimeric albumin such as the N-terminal of HSA and the C-terminal of macaca albumin (SEQ ID NO: 20), N-terminal of HSA and the C-terminal of mouse albumin (SEQ ID NO: 21), N-terminal of HSA and the C-terminal of rabbit albumin (SEQ ID NO: 22), N-terminal of HSA and the C-terminal of sheep albumin (SEQ ID NO: 23).

Other examples of albumin, which are also included in the scope of this application, include ovalbumin (e.g. P01012.pro: chicken ovalbumin; 073860.pro: turkey ovalbumin).

HSA as disclosed in SEQ ID NO: 2 or any naturally occurring allele thereof, is the preferred parent albumin according to the invention. HSA is a protein consisting of 585 amino acid residues and has a molecular weight of 67 kDa. In its natural form it is not glycosylated. The skilled person will appreciate that natural alleles may exist having essentially the same properties as HSA but having one or more (several) amino acid changes compared to SEQ ID NO: 2, and the inventors also contemplate the use of such natural alleles as parent albumin according to the invention.

The parent albumin, a fragment thereof, or albumin part of a fusion polypeptide comprising albumin or a fragment thereof according to the invention preferably has a sequence identity to the sequence of HSA shown in SEQ ID NO: 2 of at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 85%, preferably at least 86%, preferably at least 87%, preferably at least 88%, preferably at least 89%, preferably at least 90%, preferably at least 91%, preferably at least 92%, preferably at least 93%, preferably at least 94%, preferably at least 95%, more preferred at least 96%, more preferred at least 97%, more preferred at least 98% and most preferred at least 99%. It is preferred that the parent albumin maintains at least one of the major properties of albumin or a similar tertiary structure as an albumin, such as HSA. The sequence identity may be over the full-length of SEQ ID NO: 2 or over a molecule consisting or comprising of a fragment such as one or more (several) domains of SEQ ID NO: 2 such as a molecule consisting of or comprising domain III (e.g. SEQ ID NO: 27), a molecule consisting of or comprising domain II and domain III (e.g. SEQ ID NO: 25), a molecule consisting of or comprising domain I and domain III (e.g. SEQ ID NO: 24), a molecule consisting of or comprising two copies of domain III (e.g. SEQ ID NO: 26), a molecule consisting of or comprising three copies of domain III (e.g. SEQ ID NO: 28) or a molecule consisting of or comprising domain I and two copies of domain III (e.g. SEQ ID NO: 29).

The parent preferably comprises or consists of the amino acid sequence of SEQ ID NO: 4 (immature sequence of HSA) or SEQ ID NO: 2 (mature sequence of HSA).

In another embodiment, the parent is an allelic variant of the mature polypeptide of SEQ ID NO: 2.

The parent albumin may be encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) the mature polypeptide coding sequence of SEQ ID NO: 1 or (ii) the full-length complementary strand of (i) (J. Sambrook, E. F. Fritsch, and T. Maniatis, 1989, Molecular Cloning, A Laboratory Manual, 2d edition, Cold Spring Harbor, N.Y.).

The polynucleotide of SEQ ID NO: 1 or a subsequence thereof, as well as the amino acid sequence of SEQ ID NO: 2 or a fragment thereof, may be used to design nucleic acid probes to identify and clone DNA encoding a parent from strains of different genera or species according to methods well known in the art. In particular, such probes can be used for hybridization with the genomic or cDNA of the genus or species of interest, following standard Southern blotting procedures, in order to identify and isolate the corresponding gene therein. Such probes can be considerably shorter than the entire sequence, but should be at least 14, e.g., at least 25, at least 35, or at least 70 nucleotides in length. Preferably, the nucleic acid probe is at least 100 nucleotides in length, e.g., at least 200 nucleotides, at least 300 nucleotides, at least 400 nucleotides, at least 500 nucleotides, at least 600 nucleotides, at least 700 nucleotides, at least 800 nucleotides, or at least 900 nucleotides in length. Both DNA and RNA probes can be used. The probes are typically labelled for detecting the corresponding gene (for example, with ³²P, ³H, ³⁵S, biotin, or avidin). Such probes are encompassed by the invention.

A genomic DNA or cDNA library prepared from such other organisms may be screened for DNA that hybridizes with the probes described above and encodes a parent. Genomic or other DNA from such other organisms may be separated by agarose or polyacrylamide gel electrophoresis, or other separation techniques. DNA from the libraries or the separated DNA may be transferred to and immobilized on nitrocellulose or other suitable carrier material. In order to identify a clone or DNA that is homologous with SEQ ID NO: 1 or a subsequence thereof, the carrier material is used in a Southern blot.

For purposes of the invention, hybridization indicates that the polynucleotide hybridizes to a labelled nucleotide probe corresponding to the polynucleotide shown in SEQ ID NO: 1, its complementary strand, or a subsequence thereof, under low to very high stringency conditions. Molecules to which the probe hybridizes can be detected using, for example, X-ray film or any other detection means known in the art.

The nucleic acid probe may comprise or consist of the mature polypeptide coding sequence of SEQ ID NO: 1, i.e. nucleotides 1 to 1785 of SEQ ID NO: 1. The nucleic acid probe may comprise or consist of a polynucleotide that encodes the polypeptide of SEQ ID NO: 2 or a fragment thereof.

For long probes of at least 100 nucleotides in length, very low to very high stringency conditions are defined as pre-hybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and either 25% formamide for very low and low stringencies, 35% formamide for medium and medium-high stringencies, or 50% formamide for high and very high stringencies, following standard Southern blotting procedures for 12 to 24 hours optimally. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 45° C. (very low stringency), 50° C. (low stringency), 55° C. (medium stringency), 60° C. (medium-high stringency), 65° C. (high stringency), or 70° C. (very high stringency).

For short probes that are about 15 nucleotides to about 70 nucleotides in length, stringency conditions are defined as pre-hybridization and hybridization at about 5° C. to about 10° C. below the calculated Tm using the calculation according to Bolton and McCarthy (1962, Proc. Natl. Acad. Sci. USA 48: 1390) in 0.9 M NaCl, 0.09 M Tris-HCl pH 7.6, 6 mM EDTA, 0.5% NP-40, 1×Denhardt's solution, 1 mM sodium pyrophosphate, 1 mM sodium monobasic phosphate, 0.1 mM ATP, and 0.2 mg of yeast RNA per ml following standard Southern blotting procedures for 12 to 24 hours optimally. The carrier material is finally washed once in 6×SCC plus 0.1% SDS for 15 minutes and twice each for 15 minutes using 6×SSC at 5° C. to 10° C. below the calculated Tm.

The parent may be encoded by a polynucleotide with a sequence identity to the mature polypeptide coding sequence of SEQ ID NO: 1 of at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100%, which encodes a polypeptide which is able to function as an albumin. In an embodiment, the parent is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 1.

Albumin moiety: The albumin part of a fusion polypeptide, conjugate, associate, nanoparticle or composition comprising the albumin variant or fragment thereof according to the invention, may be referred to as an ‘albumin moiety’ or ‘albumin component’. A polypeptide according to the invention may comprise or consist of an albumin moiety.

FcRn and shFcRn: The term “FcRn” means the human neonatal Fc receptor (FcRn). shFcRn is a soluble recombinant form of FcRn. hFcRn is a heterodimer of SEQ ID NO: 30 (truncated heavy chain of the major histocompatibility complex class I-like Fc receptor (FCGRT)) and SEQ ID NO: 31 (beta-2-microglobulin). Together, SEQ ID NO: 30 and 31 form hFcRn.

Isolated variant: The term “isolated variant” means a variant in a form or environment which does not occur in nature. Non-limiting examples of isolated variants include (1) any non-naturally occurring variant, (2) any variant that is at least partially removed from one or more (several) or all of the naturally occurring constituents with which it is associated in nature; (3) any variant modified by the hand of man relative to the polypeptide from which it is derived (e.g. the polypeptide from which it is derived as found in nature); or (4) any variant modified by increasing the amount of the variant e relative to other components with which it is naturally associated (e.g., multiple copies of a gene encoding the substance; use of a stronger promoter than the promoter naturally associated with the gene encoding the substance). An isolated variant may be present in a fermentation broth sample.

Substantially pure variant: The term “substantially pure variant” means a preparation that contains at most 10%, at most 8%, at most 6%, at most 5%, at most 4%, at most 3%, at most 2%, at most 1%, and at most 0.5% by weight of other polypeptide material with which it is natively or recombinantly associated. Preferably, the variant is at least 92% pure, e.g., at least 94% pure, at least 95% pure, at least 96% pure, at least 97% pure, at least 98% pure, at least 99%, at least 99.5% pure, and 100% pure by weight of the total polypeptide material present in the preparation. Purity may be determined by SDS-PAGE or GP-HPLC. The variants of the invention are preferably in a substantially pure form. This can be accomplished, for example, by preparing the variant by well-known recombinant methods and by purification methods.

Mature polypeptide: The term “mature polypeptide” means a polypeptide in its final form following translation and any post-translational modifications, such as N-terminal processing, C-terminal truncation, glycosylation, phosphorylation, etc. The mature polypeptide may be amino acids 1 to 585 of SEQ ID NO: 2, e.g. with the inclusion of alterations according to the invention and/or any post-translational modifications.

Mature polypeptide coding sequence: The term “mature polypeptide coding sequence” means a polynucleotide that encodes a mature albumin polypeptide. The mature polypeptide coding sequence may be nucleotides 1 to 1758 of SEQ ID NO: 1 e.g. with the alterations required to encode a variant according to the invention.

Sequence Identity:

The relatedness between two amino acid sequences or between two nucleotide sequences is described by the parameter “sequence identity”.

For purposes of the present invention, the sequence identity between two amino acid sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends Genet. 16: 276-277), preferably version 5.0.0 or later. The parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix. The output of Needle labeled “longest identity” (obtained using the −nobrief option) is used as the percent identity and is calculated as follows:

(Identical Residues×100)/(Length of Alignment−Total Number of Gaps in Alignment)

For purposes of the present invention, the sequence identity between two deoxyribonucleotide sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, supra) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, supra), preferably version 5.0.0 or later. The parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EDNAFULL (EMBOSS version of NCBI NUC4.4) substitution matrix. The output of Needle labeled “longest identity” (obtained using the −nobrief option) is used as the percent identity and is calculated as follows:

(Identical Deoxyribonucleotides×100)/(Length of Alignment−Total Number of Gaps in Alignment)

Fragment: The term “fragment” means a polypeptide having one or more (several) amino acids deleted from the amino and/or carboxyl terminus of an albumin and/or an internal region of albumin that has retained the ability to bind to FcRn. Fragments may consist of one uninterrupted sequence derived from HSA or it may comprise two or more sequences derived from HSA. The fragments according to the invention have a size of more than approximately 20 amino acid residues, preferably more than 30 amino acid residues, more preferred more than 40 amino acid residues, more preferred more than 50 amino acid residues, more preferred more than 75 amino acid residues, more preferred more than 100 amino acid residues, more preferred more than 200 amino acid residues, more preferred more than 300 amino acid residues, even more preferred more than 400 amino acid residues and most preferred more than 500 amino acid residues. A fragment may comprise or consist of one more domains of albumin such as DI+DII, DI+DIII, DII+DIII, DIII+DIII, DI+DIII+DIII, DIII+DIII+DIII, or fragments of such domains or combinations of domains.

Domains I, II and III may be defined with reference to HSA (SEQ ID NO: 2). For example, HSA domain I may consist of or comprise amino acids 1 to 194 (±1 to 15 amino acids) of SEQ ID NO: 2, HSA domain II may consist of or comprise amino acids 192 (±1 to 15 amino acids) to 387 (±1 to 15 amino acids) of SEQ ID NO: 2 and domain III may consist of or comprise amino acid residues 381 (±1 to 15 amino acids) to 585 (±1 to 15 amino acids) of SEQ ID NO: 2. “±1 to 15 amino acids” means that the residue number may deviate by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 amino acids to the C-terminus and/or to the N-terminus of the stated amino acid position. Examples of domains I, II and III are described by Dockal et al (The Journal of Biological Chemistry, 1999, Vol. 274(41): 29303-29310) and Kjeldsen et al (Protein Expression and Purification, 1998, Vol 13: 163-169) and are tabulated below.

Amino acid residues of HSA domains I, II and III with reference to SEQ ID NO: 2 Dockal et al Kjeldsen et al Domain I  1 to 197  1 to 192 Domain II 189 to 385 193 to 382 Domain III 381 to 585 383 to 585

The skilled person can identify domains I, II and III in non-human albumins by amino acid sequence alignment with HSA, for example using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends Genet. 16: 276-277), preferably version 3.0.0 or later. The optional parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix. Other suitable software includes MUSCLE ((Multiple sequence comparison by log-expectation, Robert C. Edgar, Version 3.6, http://www.drive5.com/muscle; Edgar (2004) Nucleic Acids Research 32(5), 1792-97 and Edgar (2004) BMC Bioinformatics, 5(1):113) which may be used with the default settings as described in the User Guide (Version 3.6, September 2005). Versions of MUSCLE later than 3.6 may also be used for any aspect of the invention). Examples of suitable alignments are provided in FIGS. 1 and 2.

It is preferred that domains have at least 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5% identity or 100% identity to Domain I, II or III of HSA (SEQ ID NO: 2).

Allelic variant: The term “allelic variant” means any of two or more alternative forms of a gene occupying the same chromosomal locus. Allelic variation arises naturally through mutation, and may result in polymorphism within populations. Gene mutations can be silent (no change in the encoded polypeptide) or may encode polypeptides having altered amino acid sequences. An allelic variant of a polypeptide is a polypeptide encoded by an allelic variant of a gene.

Coding sequence: The term “coding sequence” means a polynucleotide, which directly specifies the amino acid sequence of its translated polypeptide product. The boundaries of the coding sequence are generally determined by an open reading frame, which usually begins with the ATG start codon or alternative start codons such as GTG and TTG and ends with a stop codon such as TAA, TAG, and TGA. The coding sequence may be a DNA, cDNA, synthetic, or recombinant polynucleotide.

cDNA: The term “cDNA” means a DNA molecule that can be prepared by reverse transcription from a mature, spliced, mRNA molecule obtained from a eukaryotic cell. cDNA lacks intron sequences that may be present in the corresponding genomic DNA. The initial, primary RNA transcript is a precursor to mRNA that is processed through a series of steps, including splicing, before appearing as mature spliced mRNA.

Nucleic acid construct: The term “nucleic acid construct” means a nucleic acid molecule, either single- or double-stranded, which is isolated from a naturally occurring gene or is modified to contain segments of nucleic acids in a manner that would not otherwise exist in nature or which is synthetic. The term nucleic acid construct is synonymous with the term “expression cassette” when the nucleic acid construct contains the control sequences required for expression of a coding sequence of the invention.

Control sequences: The term “control sequences” means all nucleic acid sequences necessary for the expression of a polynucleotide encoding a variant of the invention. Each control sequence may be native (i.e. from the same gene) or foreign (i.e. from a different gene) to the polynucleotide encoding the variant or native or foreign to each other. Such control sequences include, but are not limited to, a leader, polyadenylation sequence, propeptide sequence, promoter, signal peptide sequence, and transcription terminator. At a minimum, the control sequences include a promoter, and transcriptional and translational stop signals. The control sequences may be provided with linkers for the purpose of introducing specific restriction sites facilitating ligation of the control sequences with the coding region of the polynucleotide encoding a variant.

Operably linked: The term “operably linked” means a configuration in which a control sequence is placed at an appropriate position relative to the coding sequence of a polynucleotide such that the control sequence directs the expression of the coding sequence.

Expression: The term “expression” includes any step involved in the production of the variant including, but not limited to, transcription, post-transcriptional modification, translation, post-translational modification, and secretion.

Expression vector: The term “expression vector” means a linear or circular DNA molecule that comprises a polynucleotide encoding a variant and is operably linked to control sequences that provide for its expression.

Host cell: The term “host cell” means any cell type that is susceptible to transformation, transfection, transduction, or the like with a nucleic acid construct or expression vector comprising a polynucleotide of the present invention. The term “host cell” encompasses any progeny of a parent cell that is not identical to the parent cell due to mutations that occur during replication.

Plasma half-life: Plasma half-life is ideally determined in vivo in suitable individuals. However, since it is time consuming and expensive and there inevitable are ethical concerns connected with doing experiments in animals or man it is desirable to use an in vitro assay for determining whether plasma half-life is extended or reduced. It is known that the binding of albumin to its receptor FcRn is important for plasma half-life and the correlation between receptor binding and plasma half-life is that a higher affinity of albumin to its receptor leads to longer plasma half-life. Thus for the invention a higher affinity of albumin to FcRn is considered indicative of an increased plasma half-life and a lower affinity of albumin to its receptor is considered indicative of a reduced plasma half-life.

In this application and claims the binding of albumin to its receptor FcRn is described using the term affinity and the expressions “stronger” or “weaker”. Thus, it should be understood that a molecule having a higher affinity to FcRn than HSA is considered to bind stronger to FcRn than HSA and a molecule having a lower affinity to FcRn than HSA is considered to bind weaker to FcRn than HSA.

The terms “longer plasma half-life” or “shorter plasma half-life” and similar expressions are understood to be in relationship to the corresponding parent or reference or corresponding albumin molecule. Thus, a longer plasma half-life with respect to a variant albumin of the invention means that the variant has longer plasma half-life than the corresponding albumin having the same sequences except for the alteration(s) described herein, e.g. at two or more positions corresponding to 492, 550, 573, 574 and 580 of HSA (SEQ ID NO: 2).

Reference: a reference is an albumin, fusion, conjugate, composition, associate or nanoparticle to which an albumin variant, fusion, conjugate, composition, associate or nanoparticle is compared. The reference may comprise or consist of full length albumin (such as HSA or a natural allele thereof) or a fragment thereof. A reference may also be referred to as a ‘corresponding’ albumin, fusion, conjugate, composition, associate or nanoparticle to which an albumin variant, fusion, conjugate, composition, associate or nanoparticle is compared. A reference may comprise or consist of HSA (SEQ ID NO: 2) or a fragment, fusion, conjugate, associate, nanoparticle or microparticle thereof. Preferably, the reference is identical to the polypeptide, fusion polypeptide, conjugate, composition, associate, nanoparticle or microparticle according to the invention (“being studied”) with the exception of the albumin moiety. Preferably the albumin moiety of the reference comprises or consists of an albumin (e.g. HSA, SEQ ID NO: 2) or a fragment thereof. The amino acid sequence of the albumin moiety of the reference may be longer than, shorter than or, preferably, the same (±1 to 15 amino acids) length as the amino sequence of the albumin moiety of the polypeptide, fusion polypeptide, conjugate, composition, associate, nanoparticle or microparticle according to the invention (“being studied”).

Equivalent amino acid positions: Throughout this specification amino acid positions are defined in relation to full-length mature human serum albumin (i.e. without leader sequence, SEQ ID NO: 2). However, the skilled person understands that the invention also relates to variants of non-human albumins (e.g. those disclosed herein) and/or fragments of a human or non-human albumin. Equivalent positions can be identified in fragments of human serum albumin, in animal albumins and in fragments, fusions and other derivative or variants thereof by comparing amino acid sequences using pairwise (e.g. ClustalW) or multiple (e.g. MUSCLE) alignments. For example, FIG. 1 shows that positions equivalent to 500, 550 and 573 in full length human serum albumin are easily identified in fragments of human serum albumin and in albumins of other species. Positions 500, 550 and 573 are indicated by arrows. Further details are provided in Table 1 below.

TABLE 1 Example of identification of equivalent positions in HSA, animal albumins and albumin fragments Organism Albumin Position equivalent to human (accession number Full length Fragment Total length of serum albumin (native amino acid): of protein) or fragment details mature protein 500 (K) 550 (D) 573 (K) Homo sapiens Full length — 585 500 (K) 550 (D) 573 (K) (AAA98797) Homo sapiens Fragment DI, DIII 399 314 (K) 364 (D) 387 (K) Homo sapiens Fragment DI, DIII 403 318 (K) 368 (D) 391 (K) Macaca mulatta Full length — 584 500 (K) 550 (N) 573 (P) (NP_001182578) Rattus norvegicus Full length — 584 500 (K) 550 (D) 573 (P) (AAH85359) Mus musculus Full length — 584 500 (K) 550 (D) 573 (P) (AAH49971)

FIG. 1 was generated by MUSCLE using the default parameters including output in ClustalW 1.81 format. The raw output data was shaded using BoxShade 3.21 (http://www.ch.embnet.org/software/BOX_form.html) using Output Format: RTF_new; Font Size: 10; Consensus Line: no consensus line; Fraction of sequences (that must agree for shading): 0.5; Input sequence format: ALN. Therefore, throughout this specification amino acid positions defined in human serum albumin also apply to equivalent positions in fragments, derivatives or variants and fusions of human serum albumin, animals from other species and fragments and fusions thereof. Such equivalent positions may have (i) a different residue number in its native protein and/or (ii) a different native amino acid in its native protein.

Likewise, FIG. 2 shows that equivalent positions can be identified in fragments (e.g. domains) of an albumin with reference to SEQ ID NO: 2 (HSA).

Conventions for Designations of Variants

For purposes of the present invention, the mature polypeptide disclosed in SEQ ID NO: 2 is used to determine the corresponding amino acid residue in another albumin. The amino acid sequence of another albumin is aligned with the mature polypeptide disclosed in SEQ ID NO: 2, and based on the alignment, the amino acid position number corresponding to any amino acid residue in the mature polypeptide disclosed in SEQ ID NO: 2 is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends Genet. 16: 276-277), preferably version 5.0.0 or later. The parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix.

Identification of the corresponding amino acid residue in another albumin can be determined or confirmed by an alignment of multiple polypeptide sequences using several computer programs including, but not limited to, MUSCLE (multiple sequence comparison by log-expectation; version 3.5 or later; Edgar, 2004, Nucleic Acids Research 32: 1792-1797), MAFFT (version 6.857 or later; Katoh and Kuma, 2002, Nucleic Acids Research 30: 3059-3066; Katoh et al., 2005, Nucleic Acids Research 33: 511-518; Katoh and Toh, 2007, Bioinformatics 23: 372-374; Katoh et al., 2009, Methods in Molecular Biology 537:_39-64; Katoh and Toh, 2010, Bioinformatics 26:_1899-1900), and EMBOSS EMMA employing ClustalW (1.83 or later; Thompson et al., 1994, Nucleic Acids Research 22: 4673-4680), using their respective default parameters.

When the other polypeptide (or protein) has diverged from the mature polypeptide of SEQ ID NO: 2 such that traditional sequence-based comparison fails to detect their relationship (Lindahl and Elofsson, 2000, J. Mol. Biol. 295: 613-615), other pairwise sequence comparison algorithms can be used. Greater sensitivity in sequence-based searching can be attained using search programs that utilize probabilistic representations of polypeptide families (profiles) to search databases. For example, the PSI-BLAST program generates profiles through an iterative database search process and is capable of detecting remote homologs (Atschul et al., 1997, Nucleic Acids Res. 25: 3389-3402). Even greater sensitivity can be achieved if the family or superfamily for the polypeptide has one or more representatives in the protein structure databases. Programs such as GenTHREADER (Jones, 1999, J. Mol. Biol. 287: 797-815; McGuffin and Jones, 2003, Bioinformatics 19: 874-881) utilize information from a variety of sources (PSI-BLAST, secondary structure prediction, structural alignment profiles, and solvation potentials) as input to a neural network that predicts the structural fold for a query sequence. Similarly, the method of Gough et al., 2000, J. Mol. Biol. 313: 903-919, can be used to align a sequence of unknown structure with the superfamily models present in the SCOP database. These alignments can in turn be used to generate homology models for the polypeptide, and such models can be assessed for accuracy using a variety of tools developed for that purpose.

For proteins of known structure, several tools and resources are available for retrieving and generating structural alignments. For example the SCOP superfamilies of proteins have been structurally aligned, and those alignments are accessible and downloadable. Two or more protein structures can be aligned using a variety of algorithms such as the distance alignment matrix (Holm and Sander, 1998, Proteins 33: 88-96) or combinatorial extension (Shindyalov and Bourne, 1998, Protein Engineering 11: 739-747), and implementation of these algorithms can additionally be utilized to query structure databases with a structure of interest in order to discover possible structural homologs (e.g., Holm and Park, 2000, Bioinformatics 16: 566-567).

In describing the albumin variants of the present invention, the nomenclature described below is adapted for ease of reference. The accepted IUPAC single letter or three letter amino acid abbreviation is employed. The term ‘point mutation’ and/or ‘alteration’ includes deletions, insertions and substitutions.

Substitutions.

For an amino acid substitution, the following nomenclature is used: Original amino acid, position, substituted amino acid. Accordingly, the substitution of threonine at position 226 with alanine is designated as “Thr226Ala” or “T226A”. Multiple mutations (or alterations) are separated by addition marks (“+”), e.g., “Gly205Arg+Ser411Phe” or “G205R+S411F”, representing substitutions at positions 205 and 411 of glycine (G) with arginine (R) and serine (S) with phenylalanine (F), respectively. The Figures also use (“/”), e.g., “E492T/N503D” this should be viewed as interchangeable with (“+”).

Deletions.

For an amino acid deletion, the following nomenclature is used: Original amino acid, position*. Accordingly, the deletion of glycine at position 195 is designated as “Gly195*” or “G195*”. Multiple deletions are separated by addition marks (“+”), e.g., “Gly195*+Ser411*” or “G195*+S411*”.

Insertions.

As disclosed above, an insertion may be to the N-side (upstream′, ‘X−1’) or C-side (‘downstream’, ‘X+1’) of the amino acid occupying a position (the named (or original) amino acid′, ‘X’).

For an amino acid insertion to the C-side (‘downstream’, ‘X+1’) of the original amino acid (‘X’), the following nomenclature is used: Original amino acid, position, original amino acid, inserted amino acid. Accordingly the insertion of lysine after glycine at position 195 is designated “Gly195GlyLys” or “G195GK”. An insertion of multiple amino acids is designated [Original amino acid, position, original amino acid, inserted amino acid #1, inserted amino acid #2; etc.]. For example, the insertion of lysine and alanine after glycine at position 195 is indicated as “Gly195GlyLysAla” or “G195GKA”.

In such cases the inserted amino acid residue(s) are numbered by the addition of lower case letters to the position number of the amino acid residue preceding the inserted amino acid residue(s). In the above example, the sequence would thus be:

Parent: Variant: 195 195 195a 195b G G - K - A

For an amino acid insertion to the N-side (upstream′, ‘X−1’) of the original amino acid (X), the following nomenclature is used: Original amino acid, position, inserted amino acid, original amino acid. Accordingly the insertion of lysine (K) before glycine (G) at position 195 is designated “Gly195LysGly” or “G195KG”. An insertion of multiple amino acids is designated [Original amino acid, position, inserted amino acid #1, inserted amino acid #2; etc., original amino acid]. For example, the insertion of lysine (K) and alanine (A) before glycine at position 195 is indicated as “Gly195LysAlaGly” or “G195KAG”. In such cases the inserted amino acid residue(s) are numbered by the addition of lower case letters with prime to the position number of the amino acid residue following the inserted amino acid residue(s). In the above example, the sequence would thus be:

Parent: Variant: 195 195a′ 195b′ 195 G K - A - G

Multiple Alterations.

Variants comprising multiple alterations are separated by addition marks (“+”), e.g., “Arg170Tyr+Gly195Glu” or “R170Y+G195E” representing a substitution of arginine and glycine at positions 170 and 195 tyrosine and glutamic acid, respectively.

Different Alterations.

Where different alterations can be introduced at a position, the different alterations are separated by a comma, e.g., “Arg170Tyr,Glu” represents a substitution of arginine at position 170 with tyrosine or glutamic acid. Thus, “Tyr167Gly, Ala+Arg170Gly,Ala” designates the following variants: “Tyr167Gly+Arg170Gly”, “Tyr167Gly+Arg170Ala”, “Tyr167Ala+Arg170Gly”, and “Tyr167Ala+Arg170Ala”.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to albumin variants, comprising an alteration at two or more positions selected among the group consisting of positions 492, 550, 573, 574 and 580 of the mature polypeptide of SEQ ID NO: 2, or at equivalent positions in other albumins or fragments thereof.

Variants

A first aspect of the invention provides polypeptides which are variant albumins or fragments thereof, or fusion polypeptides comprising the variant albumin or fragments thereof, of a parent albumin, comprising alterations at two or more positions corresponding to positions selected among the group consisting of positions 492, 550, 573, 574 and 580 of the mature polypeptide of SEQ ID NO: 2. It is preferred that the two or more alterations comprise alterations at positions corresponding to the following positions in SEQ ID NO: 2:

(a) 492 and 580; and/or

(b) 492 and 574; and/or

(c) 492 and 550; and/or

(d) 550 and 573; and/or

(e) 550 and 574; and/or

(f) 550 and 580; and/or

and/or that

(g) the two or more alterations comprise:

an alteration to generate at a position corresponding to position 492 of SEQ ID NO: 2 an amino acid from the group consisting of A, C, D, F, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, preferably D and an alteration to generate at a position corresponding to position 573 of SEQ ID NO: 2 to an amino acid from the group consisting of C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H or

an alteration to generate at a position corresponding to position 492 of SEQ ID NO: 2 a G and an alteration to generate at a position corresponding to position 573 an A or P and an additional alteration at a position selected from the group consisting of 550, 574 and 580; and/or

(h) the two or more alterations comprise:

an alteration to generate at a position corresponding to position 573 of SEQ ID NO: 2 an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H and an alteration to generate at a position corresponding to position 574 of SEQ ID NO: 2 an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, P, Q, R, S, T, V, W, Y, H, D, F, G, N, S or Y, more preferably H, D, F or G, most preferably H or

an alteration to generate at a position corresponding to position 573 of SEQ ID NO: 2 a P and an alteration to generate at a position corresponding to position 574 of SEQ ID NO: 2 an N and an additional alteration at a position selected from the group consisting of 492, 550, and 580; and/or

(i) the two or more alterations comprise:

an alteration to generate at a position corresponding to position 573 of SEQ ID NO: 2 an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H and an alteration to generate at a position corresponding to position 580 of SEQ ID NO: 2 an amino acid from the group consisting of C, D, E, F, G, H, I, L, M, N, P, R, S, T, V, W, Y or

an alteration to generate at a position corresponding to position 573 of SEQ ID NO: 2 a P and an alteration to generate at a position corresponding to position 580 of SEQ ID NO: 2 a K and an additional alteration at a position selected from the group consisting of 492, 550, and 574; and/or

(j) the two or more alterations comprise:

an alteration to generate at a position corresponding to position 574 of SEQ ID NO: 2 an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, P, Q, R, S, T, V, W, Y, H, D, F, G, N, S or Y, more preferably H and an alteration to generate at a position corresponding to position 580 of SEQ ID NO: 2 to an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, P, R, S, T, V, W, Y or

an alteration to generate at a position corresponding to position 574 of SEQ ID NO: 2 an N and an alteration to generate at a position corresponding to position 580 of SEQ ID NO: 2 a K and an additional alteration at a position selected from the group consisting of 492, 550, and 573.

The polypeptide may comprise, three or more, four or more or five or more alterations as described in paragraphs (a), (b), (c), (d), (e), (f), (g), (h), (i) and (j).

A preferred alteration is a substitution.

It is preferred that the parent albumin and/or the variant albumin comprises or consists of:

(a) a polypeptide having at least 60% sequence identity to the mature polypeptide of SEQ ID NO: 2;

(b) a polypeptide encoded by a polynucleotide that hybridizes under low stringency conditions with (i) the mature polypeptide coding sequence of SEQ ID NO: 1, or (ii) the full-length complement of (i);

(c) a polypeptide encoded by a polynucleotide having at least 60% identity to the mature polypeptide coding sequence of SEQ ID NO: 1; and/or

(d) a fragment of the mature polypeptide of SEQ ID NO: 2.

The variants of albumin or fragments thereof or fusion polypeptides comprising albumin or fragments thereof comprise alterations, such as substitutions, deletions or insertions at two or more of positions selected among the group consisting of positions 492, 550, 573, 574 and 580 of the mature polypeptide of SEQ ID NO: 2 or in equivalent positions of other albumins or variants or fragments thereof. A stop codon may be introduced in addition to the alterations described herein and if introduced is at position 574 or further downstream (e.g. in SEQ ID NO: 2 it is introduced at from position 574 to 585).

The variant albumin, a fragment thereof, or albumin part of a fusion polypeptide comprising variant albumin or a fragment thereof according to the invention has generally a sequence identity to the sequence of HSA shown in SEQ ID NO: 2 of at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 85%, preferably at least 90%, more preferred at least 95%, more preferred at least 96%, more preferred at least 97%, more preferred at least 98% and most preferred at least 99%. The variant has less than 100% identity to SEQ ID NO: 2.

The variant albumin, a fragment thereof, or albumin part of a fusion polypeptide comprising variant albumin or a fragment thereof according to the invention has generally a sequence identity to the sequence of the parent albumin of at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 85%, preferably at least 90%, more preferred at least 95%, more preferred at least 96%, more preferred at least 97%, more preferred at least 98% and most preferred at least 99%. The variant has less than 100% identity to the sequence of the parent albumin.

In one aspect, the number of alterations in the variants of the invention is 1 to 20, e.g., 1 to 10 and 1 to 5, such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 alterations relative to SEQ ID NO: 2 or relative to the sequence of the parent albumin.

At position 492 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to G, D, F, H, M or R, even more preferred to G, or D and most preferred to G. In SEQ ID NO: 2 the native amino acid at position 492 is E, therefore a substitution to E is not preferred.

At position 550 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to K, L, M, E or R, even more preferred to K, L or M and most preferred to K. In SEQ ID NO: 2 the native amino acid at position 550 is D, therefore a substitution to D is not preferred.

At position 573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to P, Y, W, H, F, T, I or V, even more preferred to P, Y or W and most preferred to P. In SEQ ID NO: 2 the native amino acid at position 573 is K, therefore a substitution to K is not preferred.

At position 574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to H, G, D, F, N, S or Y, even more preferred to D, F, G or H and most preferred to H. In SEQ ID NO: 2 the native amino acid at position 574 is K, therefore a substitution to K is not preferred.

At position 580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to K or R, most preferred to K. In SEQ ID NO: 2 the native amino acid at position 580 is Q, therefore a substitution to Q is not preferred.

A variant albumin may comprise alterations at positions corresponding to positions 492+550 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K (e.g. SEQ ID NO: 231), or 492G+550K (e.g. SEQ ID NO: 240).

A variant albumin may comprise alterations at positions corresponding to positions 492+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492F+573P (e.g. SEQ ID NO: 109), 492G+573P (e.g. SEQ ID NO: 110), 492H+573P (e.g. SEQ ID NO: 111) or 492R+573P (e.g. SEQ ID NO: 113) or more preferably 492D+573P (e.g. SEQ ID NO: 108). However, it is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations 492G+573A, 492G+573A, 492G+N503K+573A, 492G+N503H+573A, 492G+573P, 492G+N503K+573P or 492G+N503H+573P.

A variant albumin may comprise alterations at positions corresponding to positions 492+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+574H (e.g. SEQ ID NO: 232), 492G+574H (e.g. SEQ ID NO: 241) or 492D+574H (e.g. SEQ ID NO: 232).

A variant albumin may comprise alterations at positions corresponding to positions 492+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 550+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+573P (e.g. SEQ ID NO: 117).

A variant albumin may comprise alterations at positions corresponding to positions 550+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+574H (e.g. SEQ ID NO: 130), 550M+574H (e.g. SEQ ID NO: 249), 550M+574H (e.g. SEQ ID NO: 249) or 550L+574H (e.g. SEQ ID NO: 245).

A variant albumin may comprise alterations at positions corresponding to positions 550+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+580K (e.g. SEQ ID NO: 131), 550M+580K (e.g. SEQ ID NO: 251) or 550L+580K (e.g. SEQ ID NO: 247).

A variant albumin may comprise alterations at positions corresponding to positions 573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 574D+573P (e.g. SEQ ID NO: 121), 574F+573P (e.g. SEQ ID NO: 122), 574G+573P (e.g. SEQ ID NO: 123), 574H+573P (e.g. SEQ ID NO: 124), 574N+573P (e.g. SEQ ID NO: 125) or 5745+573P (e.g. SEQ ID NO: 126). It is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations K573P+K574N+A577T+A578R+5579C+Q580K+A581D+G584A.

A variant albumin may comprise alterations at positions corresponding to positions 573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 580K+573P (e.g. SEQ ID NO: 128) or 580R+573P (e.g. SEQ ID NO: 129). However, it is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations K573P+A577E+A578S+Q580K+A582T.

A variant albumin may comprise alterations at positions corresponding to positions 574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492G+550K+573P (e.g. SEQ ID NO: 254) or 492D+550K+573P (e.g. SEQ ID NO: 253).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492G+550K+574H (e.g. SEQ ID NO: 255).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+580K (e.g. SEQ ID NO: 258) or 492G+550K+580K (e.g. SEQ ID NO: 259).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+574H (e.g. SEQ ID NO: 233).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+580K (e.g. SEQ ID NO: 234) or 492G+573P+580K (e.g. SEQ ID NO: 242).

A variant albumin may comprise alterations at positions corresponding to positions 492+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+574H+580K (SEQ ID NO: 262) or 492G+574H+580K (e.g. SEQ ID NO: 263).

A variant albumin may comprise alterations at positions corresponding to positions 50+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+574H+573P (e.g. SEQ ID NO: 131), 550L+573P+574H (e.g. SEQ ID NO: 246) or 550M+573P+574H (e.g. SEQ ID NO: 250).

A variant albumin may comprise alterations at positions corresponding to positions 550+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550L+573P+580K (e.g. SEQ ID NO: 248) or 550M+573P+580K (e.g. SEQ ID NO: 252).

A variant albumin may comprise alterations at positions corresponding to positions 550+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 574H+580K+573P (e.g. SEQ ID NO: 135).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492G+550K+573P+574H (e.g. SEQ ID NO: 257) or 492D+550K+573P+574H (e.g. SEQ ID NO: 256).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+573P+580K (e.g. SEQ ID NO: 260) or 492G+550K+573P+580K (e.g. SEQ ID NO: 261).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+574H+580K (e.g. SEQ ID NO: 114) or 492G+573P+574H+580K (e.g. SEQ ID NO: 115), 492F+573P+574G+580K (e.g. SEQ ID NO: 238), 492G+573P+574G+580K (e.g. SEQ ID NO: 234), 492D+573P+574G+580K (e.g. SEQ ID NO: 235), 492F+573P+574H+580R (e.g. SEQ ID NO: 239), 492D+573P+574H+580K (e.g. SEQ ID NO: 264), 492G+573P+574H+580R (e.g. SEQ ID NO: 244), 492D+573P+574H+580R (e.g. SEQ ID NO: 236) or 492F+573P+574H+580K (e.g. SEQ ID NO: 237).

A variant albumin may comprise alterations at positions corresponding to positions 550+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+573P+574H+580K (e.g. SEQ ID NO: 265).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+573P+574H+580K (e.g. SEQ ID NO: 266) or 492G+550K+573P+574H+580K (e.g. SEQ ID NO: 267). Such alterations may comprise 492D+550K+573P+574H (e.g. SEQ ID NO: 256).

Particularly preferred variants include:

a variant albumin with alterations at positions corresponding to positions 492 and 580 in SEQ ID NO: 2, such as (i) E492G and Q580K, or (ii) E492D and Q580K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492 and 574 in SEQ ID NO: 2, such as (i) E492G and K574H, (ii) E492D and K574H, (iii) E492D and K574K, or (iv) E492G and K574K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492 and 550 in SEQ ID NO: 2, such as (i) E492G and D550K, or (ii) E492D and D550K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 573 in SEQ ID NO: 2, such as (i) D550K and K573P, (ii) D550L and K573P or (iii) D550M and K573P (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 574 in SEQ ID NO: 2, such as (i) D550K and K574H, or (ii) D550L and K574H (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 580 in SEQ ID NO: 2, such as (i) D550M and Q580K, (ii) D550L and Q580K or (iii) D550K and Q580K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 580 and 573 in SEQ ID NO: 2, such as Q580K and K573P (or equivalent positions of other albumins or variants or fragment thereof) and preferably one or more (several) other alterations such at a position selected from 492, 550 and 574. If there is a K at position 580 and a P at position 573 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 574;

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 492 and 573 in SEQ ID NO: 2, such as:

a variant albumin comprising alterations at positions corresponding to positions 492 and 573 in SEQ ID NO: 2, such as (i) E492D and K573P (or equivalent positions of other albumins or variants or fragment thereof) or (ii) E492G and K573P or (iii) E492G and K573A (or equivalent positions of other albumins or variants or fragment thereof), and preferably one or more (several) other alterations such at a position selected from 550, 574 and 580. If there is a G at position 492 and an A or P at position 573 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 550, 574 and 580 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 573 and 574 in SEQ ID NO: 2, such as K573P and K574H (or equivalent positions of other albumins or variants or fragment thereof, and preferably one or more (several) alterations such as at a position selected from 492, 550 and 580. If there is a P at position 573 and an N at position 574 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 580 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 574 and 580 in SEQ ID NO: 2, such as 574H and 580K (or equivalent positions of other albumins or variants or fragment thereof, and preferably one or more (several) alterations such as at a position selected from 492, 550 and 573. If there is a N at position 574 and a K at position 580 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 573 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492, 550 and 573 in SEQ ID NO: 2, such as E492G, D550K and K573P e.g. SEQ ID NO: 254 or such as E492D, D550K and K573P e.g. SEQ ID NO: 253;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 580 in SEQ ID NO: 2, such as D550K, K573P and Q580K e.g. SEQ ID NO: 133;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 580 in SEQ ID NO: 2, such as D550L, K573P and Q580K e.g. SEQ ID NO:248 or such as D550M, K573P and Q580K e.g. SEQ ID NO:252;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 574 in SEQ ID NO: 2, such as D550L, K573P and K574H e.g. SEQ ID NO:246;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 574 in SEQ ID NO: 2, such as D550K, K573P and K574H e.g. SEQ ID NO: 131;

a variant albumin comprising alterations at positions corresponding to positions 492, 573 and 580 in SEQ ID NO: 2, such as E492G, K573P and Q580K e.g. SEQ ID NO: 242;

a variant albumin comprising alterations at positions corresponding to positions 492, 573 and 580 in SEQ ID NO: 2, such as E492D, K573P and Q580K e.g. SEQ ID NO: 234;

a variant albumin comprising alterations at positions corresponding to positions 492, 550, 573 and 574 in SEQ ID NO: 2, such as E492D, D550K, K573P and K574H e.g. SEQ ID NO: 256;

a variant albumin comprising alterations at positions corresponding to positions 492, 550, 573 and 574 in SEQ ID NO: 2, such as E492G, D550K, K573P and K574H e.g. SEQ ID NO: 257;

a variant albumin comprising alterations at positions corresponding to positions 573, 574 and 580 in SEQ ID NO: 2, such as K573P, K574H and Q580K e.g. SEQ ID NO: 135;

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 492, 573, 574 and 580 in SEQ ID NO: 2, such as E492D, K573P, K574H and Q580K (or equivalent positions of other albumins or variants or fragment thereof), e.g. SEQ ID NO: 114;

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 492, 573, 574 and 580 in SEQ ID NO: 2, such as E492G, K573P, K574H and Q580K (or equivalent positions of other albumins or variants or fragment thereof), e.g. SEQ ID NO: 115.

It is preferred that the variant albumin does not consist of SEQ ID NO: 2 with only the following alterations: K573P+K574N+A577T+A578R+5579C+Q580K+A581D+G584A; K573P+A577E+A578S+Q580K+A582T; E492G+K573A; E492G+N503K+K573A; E492G+N503H+K573A; E492G+K573P; E492G+N503K+K573P; E492G+N503H+K573P. Such variant albumins are disclosed in WO2011/051489.

It is preferred that the variant albumin does not consist of SEQ ID NO: 2 with amino acids 573 to 585 replaced with (a) KKLVAASQAALGL, (b) PKFVAASQAALA, (c) PNLVTRCKDALA, (d) PKLVESSKATLG or (e) PKLVASTQAALA.

It is preferred that the variant albumin, a fragment thereof or fusion polypeptide comprising the variant albumin or fragment thereof has altered binding affinity to FcRn and/or an altered plasma half-life compared with the corresponding parent or reference albumin, fragment thereof, or fusion polypeptide comprising the variant albumin or fragment thereof and/or an altered binding affinity to FcRn.

In a particularly preferred embodiment the parent or reference albumin is HSA (SEQ ID NO: 2) and the variant albumin, a fragment thereof or fusion polypeptide comprising the variant albumin or fragment thereof has altered binding affinity to FcRn and/or an altered plasma half-life compared with the HSA, the corresponding fragment or fusion polypeptide comprising HSA or fragment thereof and/or an altered binding affinity to FcRn.

The correlation between binding of albumin to its receptor and plasma half-life has been realized by the present inventors based on the natural occurring allele of HSA D494N. The inventors have previously analyzed this allele and found that it has a lower affinity to its receptor FcRn than the affinity of WT HSA to FcRn.

Further, it has been disclosed that a transgenic mouse having the natural mouse FcRn replaced with human FcRn has a higher serum albumin level than normal mouse (J Exp Med. (2003) 197(3):315-22). It has previously been discovered that human FcRn has a higher affinity to mouse serum albumin than mouse FcRn has to mouse serum albumin and, therefore, the observed increase in serum albumin in the transgenic mice corresponds with a higher affinity between serum albumin and its receptor, confirming the correlation between albumin binding to FcRn and plasma half-life. In addition, variants of albumin that have little or no binding to FcRn have been shown to have reduced half-life in a mouse model, Kenanova et al (2009) J. Nucl. Med.; 50 (Supplement 2):1582).

One way to determine whether the affinity of a variant albumin to FcRn is higher or lower than the parent or reference albumin is to use the Surface Plasmon Resonance assay (SPR) as described below. The skilled person will understand that other methods might be useful to determine whether the affinity of a variant albumin to FcRn is higher or lower than the affinity of the parent or reference albumin to FcRn, e.g., determination and comparison of the binding constants KD. The binding affinity (KD) between a first molecule (e.g. ligand) and a second molecule (e.g. receptor) is a function of the kinetic constants for association (on rate, k_(a)) and dissociation (off-rate, k_(d)) according to KD=k_(d)/k_(a). Thus, according to the invention variant albumins having a KD that is lower than the KD for natural HSA is considered to have a higher plasma half-life than HSA and variant albumins having a KD that is higher than the KD for natural HSA is considered to have a lower plasma half-life than HSA.

In an embodiment of the invention, the variants of albumin or fragments thereof, or fusion polypeptides comprising variant albumin or a fragment thereof according to the invention have a plasma half-life that is longer than the plasma half-life of the parent or reference albumin fragment thereof or fusion polypeptide comprising the parent or reference albumin or a fragment thereof and/or an stronger binding affinity to FcRn.

In a further embodiment the variants of albumin or fragments thereof, or fusion polypeptides comprising variant albumin or fragments thereof according to the invention have a plasma half-life that is shorter than the plasma half-life of the parent or reference albumin fragment thereof or fusion polypeptide comprising the parent or reference albumin or a fragment thereof and/or an weaker binding affinity to FcRn.

In addition to alterations at two or more positions selected from 492, 550, 573, 574 and/or 580 (or equivalent position of other albumins or variants or fragments thereof) the variant albumin or fragments thereof, or fusion polypeptides comprising variant albumin or fragments thereof according to the invention may contain additional substitutions, deletions or insertions in other positions of the molecules. Such additional substitutions, deletions or insertions may be useful in order to alter other properties of the molecules such as but not limited to altered glycosylation; introduction of reactive groups of the surface such a thiol groups, removing/generating a carbamoylation site; etc.

Residues that might be altered in order to provide reactive residues on the surface and which advantageously could be applied to the invention has been disclosed in WO2010/092135 (incorporated herein by reference). Particular preferred residues include the positions corresponding to positions in SEQ ID NO: 2.

As examples of alterations that can be made in SEQ ID NO: 2 or in corresponding positions in other albumins in order to provide a reactive thiol group on the surface includes alterations corresponding to following alterations in SEQ ID NO: 2: L585C, D1C, A2C, D562C, A364C, A504C, E505C, T79C, E86C, D129C, D549C, A581C, D121C, E82C, S270C, A578C, L595LC, D1DC, A2AC, D562DC, A364AC, A504AC, E505EC, T79TC, E86EC, D129DC, D549DC, A581AC, A581AC, D121DC, E82EC, S270SC, A579AC, C360*, C316*, C75*, C168*, C558*, C361*, C91*, C124*, C169* and C567*. Alternatively a cysteine residue may be added to the N or C terminal of albumin. The term ‘reactive thiol’ means and/or includes a thiol group provided by a Cys which is not disulphide bonded to a Cysteine and/or which is sterically available for binding to a partner such as a conjugation partner.

Fusion Polypeptides

A second aspect of the invention relates to fusion polypeptides. Therefore, the variants of albumin or fragments thereof according to the invention may be fused with a non-albumin polypeptide fusion partner. The fusion partner may in principle be any polypeptide but generally it is preferred that the fusion partner is a polypeptide having therapeutic, prophylactic (including vaccine), diagnostic, imaging or other beneficial properties. Such properties may be referred to as ‘pharmaceutically beneficial properties’. Fusion polypeptides comprising albumin or fragments thereof are known in the art. It has been found that such fusion polypeptides comprising albumin or a fragment thereof and a fusion partner polypeptide have a longer plasma half-life compared to the unfused fusion partner polypeptide alone. According to the invention it is possible to alter the plasma half-life of the fusion polypeptides according to the invention compared to the corresponding fusion polypeptides of the prior art. ‘Alter’ includes both increasing the plasma half-life or decreasing the plasma half-life. Increasing the plasma half-life is preferred. The invention allows tailoring of half-life to a term desired.

One or more (several) therapeutic, prophylactic (including vaccine), diagnostic, imaging or other beneficial polypeptides may be fused to the N-terminus, the C-terminus of albumin, inserted into a loop in the albumin structure or any combination thereof. It may or it may not comprise linker sequences separating the various components of the fusion polypeptide.

Teachings relating to fusions of albumin or a fragment thereof are known in the art and the skilled person will appreciate that such teachings can also be applied to the invention. WO 2001/79271A (particularly page 9 and/or Table 1), WO 2003/59934 (particularly Table 1), WO03/060071 (particularly Table 1) and WO01/079480 (particularly Table 1) (each incorporated herein by reference in their entirety) also contain examples of therapeutic, prophylactic (including vaccine), diagnostic, imaging or other beneficial polypeptides that may be fused to albumin or fragments thereof, and these examples apply also to the invention.

Further preferences for the second aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Polynucleotides

A third aspect of the invention relates to isolated polynucleotides that encode any of the variants or fusion polypeptides of the invention. The polynucleotide may be an isolated polynucleotide. The polynucleotide may be comprised in a vector (such as a plasmid) and/or in a host cell.

Further preferences for the third aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Nucleic Acid Constructs

A fourth aspect of the invention relates to nucleic acid constructs comprising a polynucleotide encoding a variant or fusion polypeptide of the invention operably linked to one or more (several) control sequences that direct the expression of the coding sequence in a suitable host cell under conditions compatible with the control sequences.

A polynucleotide may be manipulated in a variety of ways to provide for expression of a variant. Manipulation of the polynucleotide prior to its insertion into a vector may be desirable or necessary depending on the expression vector. The techniques for modifying polynucleotides utilizing recombinant DNA methods are well known in the art.

The control sequence may be a promoter sequence, which is recognized by a host cell for expression of the polynucleotide. The promoter sequence contains transcriptional control sequences that mediate the expression of the variant. The promoter may be any nucleic acid sequence that shows transcriptional activity in the host cell including mutant, truncated, and hybrid promoters, and may be obtained from genes encoding extracellular or intracellular polypeptides either homologous or heterologous to the host cell.

In a yeast host, useful promoters are obtained from the genes for Saccharomyces cerevisiae enolase (ENO-1), Saccharomyces cerevisiae protease A (PRA1), Saccharomyces cerevisiae protease B (PRB1), Saccharomyces cerevisiae translation elongation factor (TEF1), Saccharomyces cerevisiae translation elongation factor (TEF2), Saccharomyces cerevisiae galactokinase (GAL1), Saccharomyces cerevisiae alcohol dehydrogenase/glyceraldehyde-3-phosphate dehydrogenase (ADH1, ADH2/GAP), Saccharomyces cerevisiae triose phosphate isomerase (TPI), Saccharomyces cerevisiae metallothionein (CUP1), and Saccharomyces cerevisiae 3-phosphoglycerate kinase. Other useful promoters for yeast host cells are described by Romanos et al., 1992, Yeast 8: 423-488.

The skilled person knows useful promoters for use in rice and mammalian cells, such as CHO or HEK. In a rice host, useful promoters are obtained from cauliflower mosaic virus 35S RNA gene (CaMV35S), maize alcohol dehydrogenase (Adh1) and alpha Amy3.

In a mammalian host cell, such as CHO or HEK, useful promoters are obtained from Cytomegalovirus (CMV) and CAG hybrid promoter (hybrid of CMV early enhancer element and chicken beta-actin promoter), Simian vacuolating virus 40 (SV40).

The control sequence may also be a suitable transcription terminator sequence, which is recognized by a host cell to terminate transcription. The terminator sequence is operably linked to the 3′-terminus of the polynucleotide encoding the variant. Any terminator that is functional in the host cell may be used.

Preferred terminators for yeast host cells are obtained from the genes for Saccharomyces cerevisiae enolase, Saccharomyces cerevisiae cytochrome C (CYC1), Saccharomyces cerevisiae alcohol dehydrogenase (ADH1) and Saccharomyces cerevisiae glyceraldehyde-3-phosphate dehydrogenase. Other useful terminators for yeast host cells are described by Romanos et al., 1992, supra. The skilled person knows useful terminators for use in rice and mammalian cells, such as CHO or HEK. For example, in a rice host, preferred terminators are obtained from Agrobacterium tumefaciens nopaline synthase (Nos) and cauliflower mosaic virus 35S RNA gene (CaMV35S).

The control sequence may also be a suitable leader sequence, a nontranslated region of an mRNA that is important for translation by the host cell. The leader sequence is operably linked to the 5′-terminus of the polynucleotide encoding the variant. Any leader sequence that is functional in the host cell may be used.

Suitable leaders for yeast host cells are obtained from the genes for Saccharomyces cerevisiae enolase (ENO-1), Saccharomyces cerevisiae 3-phosphoglycerate kinase, Saccharomyces cerevisiae alpha-factor, and Saccharomyces cerevisiae alcohol dehydrogenase/glyceraldehyde-3-phosphate dehydrogenase (ADH2/GAP).

The control sequence may also be a polyadenylation sequence, a sequence operably linked to the 3′-terminus of the variant-encoding sequence and, when transcribed, is recognized by the host cell as a signal to add polyadenosine residues to transcribed mRNA. Any polyadenylation sequence that is functional in the host cell may be used.

Useful polyadenylation sequences for yeast host cells are described by Guo and Sherman, 1995, Mol. Cellular Biol. 15: 5983-5990.

The control sequence may also be a signal peptide coding region that encodes a signal peptide linked to the N-terminus of a variant and directs the variant into the cell's secretory pathway. The 5′-end of the coding sequence of the polynucleotide may inherently contain a signal peptide coding region naturally linked in translation reading frame with the segment of the coding region that encodes the variant. Alternatively, the 5′-end of the coding sequence may contain a signal peptide coding region that is foreign to the coding sequence. The foreign signal peptide coding region may be required where the coding sequence does not naturally contain a signal peptide coding region. Alternatively, the foreign signal peptide coding region may simply replace the natural signal peptide coding region in order to enhance secretion of the variant. However, any signal peptide coding region that directs the expressed variant into the secretory pathway of a host cell may be used.

Useful signal peptides for yeast host cells are obtained from the genes for Saccharomyces cerevisiae alpha-factor and Saccharomyces cerevisiae invertase. Other useful signal peptide coding sequences are described by Romanos et al., 1992, supra. The skilled person knows useful signal peptides for use in rice and mammalian cells, such as CHO or HEK.

Where both signal peptide and propeptide regions are present at the N-terminus of a variant, the propeptide region is positioned next to the N-terminus of the variant and the signal peptide region is positioned next to the N-terminus of the propeptide region.

Further preferences for the fourth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Preparation of Variants

A fifth aspect of the invention relates to a method for preparing or obtaining a variant albumin or fragment thereof, or fusion polypeptides comprising the variant albumin or fragments thereof, or associates of variant albumin or fragment thereof comprising:

(a) introducing into a parent albumin or fragments thereof, or fusion polypeptides comprising the parent albumin or fragments thereof an alteration at two or more positions selected from 492, 550, 573, 574 and 580, preferably as described for the first aspect of the invention; and

(b) recovering the variant albumin or fragment thereof, or fusion polypeptides comprising the variant albumin or fragment thereof.

Preferred alterations are as described in relation to the first aspect of the invention. The resultant variant albumin or fragment thereof may have altered FcRn-binding affinity compared to the FcRn-binding affinity of a reference such as a parent albumin or fragment which does not comprise the alterations. More preferably, the resultant variant albumin or fragment thereof has a stronger FcRn-binding affinity.

The invention includes a method for preparing a polypeptide which is a variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof having a binding affinity to FcRn which is altered compared to the binding affinity of a reference albumin, fragment or fusion thereof to FcRn, comprising:

(a) providing a nucleic acid encoding a parent albumin such as an albumin having at least 60% sequence identity to SEQ ID NO: 2;

(b) modifying the sequence of step (a), to encode a polypeptide which is a variant albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof comprising alterations at two or more positions corresponding to positions selected from selected among two or more of the group consisting of positions 492, 550, 573, 574 and 580 in SEQ ID NO: 2;

(c) optionally, introducing the modified sequence of step (b) in a suitable host cell;

(d) optionally, growing the cells in a suitable growth medium under condition leading to expression of the polypeptide; and

(e) optionally, recovering the polypeptide from the growth medium;

wherein the polypeptide has an altered binding affinity to FcRn and/or an altered plasma half-life compared with the half-life of a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof.

It is preferred that the parent albumin and/or the variant albumin comprises or consists of:

(a) a polypeptide having at least 60% sequence identity to the mature polypeptide of SEQ ID NO: 2;

(b) a polypeptide encoded by a polynucleotide that hybridizes under low stringency conditions with (i) the mature polypeptide coding sequence of SEQ ID NO: 1, or (ii) the full-length complement of (i);

(c) a polypeptide encoded by a polynucleotide having at least 60% identity to the mature polypeptide coding sequence of SEQ ID NO: 1; and/or

(d) a fragment of the mature polypeptide of SEQ ID NO: 2.

The variants can be prepared by those skilled persons using any mutagenesis procedure known in the art, such as site-directed mutagenesis, synthetic gene construction, semi-synthetic gene construction, random mutagenesis, shuffling, etc.

Site-directed mutagenesis is a technique in which one or more (several) mutations (alterations) are created at one or more (several) defined sites in a polynucleotide encoding the parent.

Site-directed mutagenesis can be accomplished in vitro by PCR involving the use of oligonucleotide primers containing the desired mutation. Site-directed mutagenesis can also be performed in vitro by cassette mutagenesis involving the cleavage by a restriction enzyme at a site in the plasmid comprising a polynucleotide encoding the parent and subsequent ligation of an oligonucleotide containing the mutation in the polynucleotide. Usually the restriction enzyme that digests at the plasmid and the oligonucleotide is the same, permitting ligation of the plasmid and insert to one another. See, e.g., Scherer and Davis, 1979, Proc. Natl. Acad. Sci. USA 76: 4949-4955; and Barton et al., 1990, Nucleic Acids Res. 18: 7349-4966.

Site-directed mutagenesis can also be accomplished in vivo by methods known in the art. See, e.g., U.S. Patent Application Publication NO: 2004/0171154; Storici et al., 2001, Nature Biotechnol. 19: 773-776; Kren et al., 1998, Nat. Med. 4: 285-290; and Calissano and Macino, 1996, Fungal Genet. Newslett. 43: 15-16.

Any site-directed mutagenesis procedure can be used in the invention. There are many commercial kits available that can be used to prepare variants.

Synthetic gene construction entails in vitro synthesis of a designed polynucleotide molecule to encode a polypeptide of interest. Gene synthesis can be performed utilizing a number of techniques, such as the multiplex microchip-based technology described by Tian et al. (2004, Nature 432: 1050-1054) and similar technologies wherein oligonucleotides are synthesized and assembled upon photo-programmable microfluidic chips.

Single or multiple amino acid substitutions, deletions, and/or insertions can be made and tested using known methods of mutagenesis, recombination, and/or shuffling, followed by a relevant screening procedure, such as those disclosed by Reidhaar-Olson and Sauer, 1988, Science 241: 53-57; Bowie and Sauer, 1989, Proc. Natl. Acad. Sci. USA 86: 2152-2156; WO 95/17413; or WO 95/22625. Other methods that can be used include error-prone PCR, phage display (e.g., Lowman et al., 1991, Biochemistry 30: 10832-10837; U.S. Pat. No. 5,223,409; WO 92/06204) and region-directed mutagenesis (Derbyshire et al., 1986, Gene 46: 145; Ner et al., 1988, DNA 7: 127).

Mutagenesis/shuffling methods can be combined with high-throughput, automated screening methods to detect activity of cloned, mutagenized polypeptides expressed by host cells (Ness et al., 1999, Nature Biotechnology 17: 893-896). Mutagenized DNA molecules that encode active polypeptides can be recovered from the host cells and rapidly sequenced using standard methods in the art. These methods allow the rapid determination of the importance of individual amino acid residues in a polypeptide.

Semi-synthetic gene construction is accomplished by combining aspects of synthetic gene construction, and/or site-directed mutagenesis, and/or random mutagenesis, and/or shuffling. Semi-synthetic construction is typified by a process utilizing polynucleotide fragments that are synthesized, in combination with PCR techniques. Defined regions of genes may thus be synthesized de novo, while other regions may be amplified using site-specific mutagenic primers, while yet other regions may be subjected to error-prone PCR or non-error prone PCR amplification. Polynucleotide sub sequences may then be shuffled.

Further preferences for the fifth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Methods of Production

A sixth aspect of the invention relates to methods of preparation of a variant according to the invention. The variants of the invention can be prepared using techniques well known to the skilled person. One convenient way is by cloning nucleic acid encoding the parent albumin or a fragment thereof or fusion polypeptide comprising albumin or a fragment thereof, modifying said nucleic acid to introduce the desired substitution(s) at two or more positions corresponding to positions selected from 492, 550, 573, 574 and 580 of the mature polypeptide of SEQ ID NO: 2 (or equivalent positions in other albumins or fragments thereof), preferably as described for the first or fifth aspects of the invention, preparing a suitable genetic construct where the modified nucleic acid is placed in operative connection with suitable regulatory genetic elements, such as promoter, terminator, activation sites, ribosome binding sites etc., introducing the genetic construct into a suitable host organism, culturing the transformed host organism under conditions leading to expression of the variant and recovering the variant. All these techniques are known in the art and it is within the skills of the average practitioner to design a suitable method for preparing a particular variant according to the invention.

The variant polypeptide of the invention may also be connected to a signal sequence in order to have the variant polypeptide secreted into the growth medium during culturing of the transformed host organism. It is generally advantageous to have the variant polypeptide secreted into the growth medium in order to ease recovery and purification.

Techniques for preparing variant polypeptides have also been disclosed in WO 2009019314 (included by reference) and these techniques may also be applied to the invention.

Albumins have been successfully expressed as recombinant proteins in a range of hosts including fungi (including but not limited to Aspergillus (WO06066595), Kluyveromyces (Fleer 1991, Bio/technology 9, 968-975), Pichia (Kobayashi 1998 Therapeutic Apheresis 2, 257-262) and Saccharomyces (Sleep 1990, Bio/technology 8, 42-46)), bacteria (Pandjaitab 2000, J. Allergy Clin. Immunol. 105, 279-285)), animals (Barash 1993, Transgenic Research 2, 266-276) and plants (including but not limited to potato and tobacco (Sijmons 1990, Bio/technology 8, 217 and Farran 2002, Transgenic Research 11, 337-346) and rice e.g. Oryza sativa) and mammalian cells such as CHO and HEK. The variant polypeptide of the invention is preferably produced recombinantly in a suitable host cell. In principle any host cell capable of producing a polypeptide in suitable amounts may be used and it is within the skills of the average practitioner to select a suitable host cell according to the invention. A preferred host organism is yeast, preferably selected among Saccharomycacae, more preferred Saccharomyces cerevisiae.

The variant polypeptides of the invention may be recovered and purified from the growth medium using a combination of known separation techniques such as filtration, centrifugation, chromatography, and affinity separation techniques etc. It is within the skills of the average practitioner to purify the variants of the invention using a particular combination of such known separation steps. As an example of purification techniques that may be applied to the variants of the invention can be mentioned the teaching of WO00/44772.

The variant polypeptides of the invention may be used for delivering a therapeutically beneficial compound (including prophylactically beneficial compound such as a vaccine) to an animal or a human individual in need thereof. Such therapeutically beneficial compounds include, but are not limited, to labels and readily detectable compounds for use in diagnostics, such as various imaging techniques; pharmaceutical active compounds such as drugs, or specifically binding moieties such as antibodies. The variants of the invention may even be connected to two or more different therapeutically beneficial compounds, e.g., an antibody and a drug, which gives the combined molecule the ability to bind specifically to a desired target and thereby provide a high concentration of the connected drug at that particular target.

Further preferences for the sixth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Conjugates

A seventh aspect of the invention relates to conjugates (conjugations). Therefore, the variants of albumin or fragments thereof or fusion polypeptides according to the invention may be conjugated to a second molecule (conjugation partner′) using techniques known within the art. The conjugation partner may be a therapeutic, prophylactic (including vaccine), diagnostic, imaging or other beneficial moiety. Said conjugation partner may be a polypeptide or a non-polypeptide chemical. The conjugation partner may be a polypeptide, chemical (e.g. chemically synthesised drug) or a nucleic acid (e.g. DNA, RNA, siRNA).

Said second molecule may comprise a diagnostic or imaging moiety, and in this embodiment the conjugate may be useful as a diagnostic tool such as in imaging; or the second molecule may be a therapeutic or prophylactic (e.g. vaccine) compound and in this embodiment the conjugate may be used for therapeutic or prophylactic (e.g. vaccination) purposes where the conjugate will have the therapeutic or prophylactic properties of the therapeutic or prophylactic compound as well as the desirable plasma half-life provided by the albumin part of the conjugate. Conjugates of albumin and a therapeutic molecule are known in the art and it has been verified that such conjugates have long plasma half-life compared with the non-conjugated, free therapeutic molecule as such. According to the invention it is possible to alter the binding affinity to FcRn and/or plasma half-life of the conjugate according to the invention compared to the corresponding conjugates of the prior art. ‘Alter’ includes both increasing the plasma half-life and decreasing the plasma half-life binding affinity to FcRn and/or increasing the binding affinity and decreasing the binding affinity to FcRn. Increasing the plasma half-life and/or binding affinity to FcRn is preferred. The conjugates may conveniently be linked via a free thiol group present on the surface of HSA (amino acid residue 34 of mature HSA) using well known chemistry.

In one particular preferred aspect the variant albumin or fragment thereof is conjugated to a beneficial therapeutic or prophylactic (including vaccine) compound and the conjugate is used for treatment of a condition in a patient in need thereof, which condition is responsive to the particular selected therapeutic compound. Techniques for conjugating such a therapeutically useful compound to the variant albumin or fragment thereof are known in the art. WO 2009/019314 (incorporated herein by reference in its entirety) discloses examples of techniques suitable for conjugating a therapeutically compound to a polypeptide which techniques can also be applied to the invention. Further WO 2009/019314 discloses examples of compounds and moieties that may be conjugated to substituted transferrin and these examples may also be applied to the invention. The teaching of WO 2009/019314 is included herein by reference.

HSA contains in its natural form one free thiol group (at Cys34) that conveniently may be used for conjugation. As a particular embodiment within this aspect the variant albumin or fragment thereof may comprise further modifications provided to generate additional free thiol groups on the surface. This has the benefit that the payload of the variant albumin or fragment thereof is increased so that more than one molecule of the therapeutic (e.g. prophylactic) compound can be conjugated to each molecule of variant albumin or fragment thereof, or two or more (several) different therapeutic compounds may be conjugated to each molecule of variant albumin or fragment thereof, e.g., a compound having targeting properties such as an antibody specific for example a tumour; and a cytotoxic drug conjugated to the variant albumin or fragment thereof thereby creating a highly specific drug against a tumour. Teaching of particular residues that may be modified to provide for further free thiol groups on the surface can be found in co-pending patent application WO 2010/092135, which is incorporated by reference.

The conjugation partner may alternatively be conjugated to a fusion polypeptide (described herein), resulting in a molecule comprising a fusion partner fused to the albumin as well as a conjugation partner conjugated to the same albumin or even to the fusion partner.

Further preferences for the seventh aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Associates

An eighth aspect of the invention relates to associates. Therefore, the variants of albumin or fragments thereof or fusion polypeptides may further be used in form of “associates”. In this connection the term “associate” is intended to mean a compound comprising a variant of albumin or a fragment thereof and another compound bound or associated to the variant albumin or fragment thereof by non-covalent binding. As an example of such an associate can be mentioned an associate consisting of variant albumin and a lipid associated to albumin by a hydrophobic interaction. Such associates are known in the art and they may be prepared using well known techniques. As an example of a preferred associate according to the invention can be mentioned, an associate comprising variant albumin and a taxane, a taxol or taxol derivative (e.g. paclitaxel). Further examples of associates comprise a therapeutic, prophylactic (including vaccine), diagnostic, imaging or other beneficial moiety.

The half-life of an albumin associate according to the invention may be longer or shorter than the half-life of the ‘other compound’ alone. The half-life of an albumin associate according to the invention may be longer or shorter than the half-life of the analogous/equivalent albumin associate comprising or consisting of a reference albumin such as native HSA (instead of an albumin variant or derivative according to the invention) and the ‘other compound’. Likewise, the binding affinity to FcRn of an albumin associate according to the invention may be stronger or weaker than the binding affinity to FcRn of the analogous/equivalent albumin associate comprising or consisting of a reference albumin such as native HSA (instead of an albumin variant or derivative according to the invention) and the ‘other compound’. Methods for the preparation of associates are well-known to the skilled person, for example, formulation (by association) of HSA with Lipo-compounds is described in Hussain, R. and Siligardi, G. (2006) International Journal of Peptide Research and Therapeutics, Vol. 12, NO: 3, pp. 311-315.

Further preferences for the eighth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Compositions

A ninth aspect of the invention relates to compositions. Therefore the invention is also directed to the use of a variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, or a conjugate comprising a variant of albumin or a fragment thereof, or an associate comprising a variant of albumin or a fragment thereof for the manufacture of a pharmaceutical composition, wherein the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, or a conjugate comprising a variant of albumin or a fragment thereof, or an associate comprising a variant of albumin or a fragment thereof has an altered binding affinity to FcRn and/or an altered plasma half-life compared with HSA or the corresponding fragment thereof or fusion polypeptide comprising HSA or fragment thereof or conjugate comprising HSA.

In this connection the corresponding fragment of HSA is intended to mean a fragment of HSA that aligns with and has same number of amino acids as the fragment of the variant albumin with which it is compared. Similarly the corresponding fusion polypeptide comprising HSA or conjugate comprising HSA is intended to mean molecules having same size and amino acid sequence as the fusion polypeptide of conjugate comprising variant albumin, with which it is compared.

The composition may comprise a pharmaceutically acceptable carrier or excipient such as water, polysorbate 80 or those specified in the US Pharmacopoeia for human albumin.

Further preferences for the ninth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Nanoparticles

A tenth aspect of the invention relates to a nanoparticle comprising a variant, fusion, conjugate, associate, nanoparticle, composition or polynucleotide as disclosed herein.

Techniques for incorporation of a molecule into nano- or microparticles are known in the art. Preferred methods for preparing nano- or microparticles that may be applied to the albumin, variant, fragment, fusion, conjugate or associate thereof according to the invention is disclosed in WO 2004/071536 or WO2008/007146 or Oner & Groves (Pharmaceutical Research, Vol 10(9), 1993, pages 1387 to 1388) which are incorporated herein by reference. Preferably the average diameter of a nano-particle is from 5 to 1000 nm, more preferably 5, 10, 20, 30, 40, 50, 80, 100, 130, 150, 200, 300, 400, 500, 600, 700, 800, 900, or 999 to 5, 10, 20, 30, 40, 50, 80, 100, 130, 150, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 nm. An advantage of a microparticle less than 200 nm diameter, and more particularly less than 130 nm, is that is amenable to sterilisation by filtration through a 0.2 μm (micron) filter. Preferably, the average diameter of a micro-particle is from 1000 nm (1 μm (micron)) to 100 μm (micron), more preferably from 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 to 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 μm (micron).

Further preferences for the tenth aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Uses

An eleventh aspect of the invention relates to use of a variant albumin, fragment, fusion or conjugate thereof or nanoparticle or associate thereof. Use may be, for example, in a method of treatment, prophylaxis, diagnosis or imaging. The variant albumin or fragments thereof or fusion polypeptides comprising variant albumin or fragments thereof according to the invention have the benefit that their binding affinity to FcRn and/or plasma half-life is altered compared to the parent or reference albumin or fragments thereof or fusion polypeptides comprising parent or reference albumin or fragments thereof. This has the advantage that the binding affinity to FcRn and/or plasma half-life of conjugates comprising variant albumin or a fragment thereof or fusion polypeptide comprising variant albumin or a fragment thereof, or an associate comprising variant albumin or a fragment thereof according to the invention can be selected in accordance with the particular therapeutic purpose.

In some situations, it would be advantageous to use an albumin, variant, fragment, fusion, conjugate or associate or composition thereof having a longer plasma half-life than the reference molecule or composition since this would have the benefit that the administration of the albumin, variant, fragment, fusion, conjugate or associate or composition thereof would be needed less frequently or at a reduced dose (and consequently with fewer side effects) compared to the situation where the reference molecule or composition was used. With respect to the use of a variant, fusion, conjugate, associate, nanoparticle, composition or polynucleotide the albumin moiety may comprise one more alterations as disclosed herein.

In other situations, it would be advantageous to use an albumin, variant, fragment, fusion, conjugate or associate or composition thereof having a shorter plasma half-life than the reference molecule or composition since this would have the benefit that the administration of the albumin, variant, fragment, fusion, conjugate or associate or composition thereof can be carried out at a higher dose compared to the situation where the reference molecule or composition was used with the benefit that the administered compound clears from the recipient more quickly than if the reference molecule or composition was used. With respect to the use of a variant, fusion, conjugate, associate, nanoparticle, composition or polynucleotide the albumin moiety may comprise one more alterations as disclosed herein.

For example for a conjugate, associate or fusion polypeptide used for imaging purposes in animals or human beings, where the imaging moiety has an very short half-life and a conjugate or a fusion polypeptide comprising HSA has a plasma half-life that is far longer than needed for the imaging purposes it would be advantageous to use a variant albumin or fragment thereof of the invention having a shorter plasma half-life than the parent or reference albumin or fragment thereof, to provide conjugates of fusion polypeptides having a plasma half-life that is sufficiently long for the imaging purpose but sufficiently short to be cleared form the body of the particular patient on which it is applied.

In another example for a conjugate, an associate or fusion polypeptide comprising a therapeutic compound effective to treat or alleviate a particular condition in a patient in need for such a treatment it would be advantageous to use the variant albumin or fragment thereof having a longer plasma half-life than the parent or reference albumin or fragment thereof, to provide associates or conjugates or fusion polypeptides having longer plasma half-lives which would have the benefit that the administration of the associate or conjugate or fusion polypeptide of the invention would be needed less frequently or at reduced dose with less side effects compared to the situation where the parent or reference albumin or associates thereof or fragment thereof was used. For example, the invention provides a method of treating a proliferative disease in an individual, comprising administering the individual an effective amount of an associate according to the invention in which the associate comprises a taxane, a taxol or taxol derivative (e.g. paclitaxel).

In a further aspect the invention relates to compositions comprising the variant albumin, associates thereof or fragment thereof, variant albumin fragment or associates thereof or fusion polypeptide comprising variant albumin or fragment thereof according to the invention. The compositions are preferably pharmaceutical compositions. The composition may be prepared using techniques known in the area such as disclosed in recognized handbooks within the pharmaceutical field. Since the albumin, variant, fragment, fusion, conjugate or associate thereof has a binding affinity to FcRn and/or plasma half-life which is modulated (i.e. stronger or weaker and/or longer or shorter) than that of a reference molecule, the composition also has a binding affinity to FcRn and/or modulated plasma half-life relative to an equivalent composition comprising the reference molecule in place of the albumin, variant, fragment, fusion, conjugate or associate thereof as described herein. The composition may be a vaccine. The polypeptide according to the invention may be an active pharmaceutical or an excipient. Optionally, the composition is provided in unit dosage form.

Preferably the albumin, variant, fragment, fusion, conjugate or associate thereof has a plasma half-life that is longer than the plasma half-life of the reference molecule e.g. the same composition except that the albumin component (e.g. albumin, variant, fragment, fusion, conjugate or associate) is wild-type albumin (e.g. HSA) or a variant, fragment, fusion, conjugate or associate.

In a particular embodiment the compositions comprise a variant albumin or a fragment thereof according to the invention and a compound comprising a pharmaceutically beneficial moiety and an albumin binding domain (ABD). According to the invention ABD means a site, moiety or domain capable of binding to circulating albumin in vivo and thereby conferring transport in the circulation of the ABD and any compound or moiety bound to said ABD. ABD's are known in the art and have been shown to bind very tight to albumin so a compound comprising an ABD bound to albumin will to a certain extent behave as a single molecule. The inventors have realized by using the variant albumin or fragment thereof according to the invention together with a compound comprising a pharmaceutically beneficial moiety and an ABD makes it possible to alter the binding affinity to FcRn and/or plasma half-life of the compound comprising a pharmaceutically beneficial moiety and an ABD compared to the situation where said compound were injected as such in a patient having need thereof or administered in a formulation comprising natural albumin or a fragment thereof.

The variant albumin or fragments thereof, conjugates comprising variant albumin or a fragment thereof or fusion polypeptide comprising variant albumin or a fragment thereof, or an associate comprising variant albumin or a fragment thereof according to the invention may also be incorporated into nano- or microparticles using techniques well known within the art. A preferred method for preparing nano- or microparticles that may be applied to the variant albumins or fragments thereof according to the invention is disclosed in WO 2004/071536 or WO2008/007146 or Oner & Groves (Pharmaceutical Research, Vol 10(9), 1993, pages 1387 to 1388) which are incorporated herein by reference.

Further preferences for the eleventh aspect of the invention include those of the first aspect of the invention and those provided below the twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Method for Altering the FcRn-Binding Affinity or Half-Life of a Molecule

A twelfth aspect of the invention provides a method for altering the FcRn-binding affinity or half-life of a molecule comprising:

(a) where the molecule is a polypeptide, fusing or conjugating the molecule to a polypeptide disclosed herein or to a conjugate disclosed herein; associating the molecule to a polypeptide disclosed herein or to a conjugate disclosed herein; incorporating the molecule in a nanoparticle disclosed herein or a composition disclosed herein;

(b) where the molecule is not a polypeptide, conjugating the molecule to a polypeptide disclosed herein or to a conjugate disclosed herein; associating the molecule to a polypeptide disclosed herein or to a conjugate a disclosed herein; incorporating the molecule in a nanoparticle disclosed herein or a composition disclosed herein.

Examples of ‘molecule’ include those useful in therapy, prophylaxis (including those used in vaccines either as an active pharmaceutical ingredient or as an excipient), imaging and diagnosis, such as those described herein.

Further preferences for the twelfth aspect of the invention include those of the first aspect of the invention and those provided below this twelfth aspect of the invention. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

Preferences for all aspects of the invention are provided below. The skilled person understands that any aspect of the invention may be combined with another aspect or aspects of the invention and/or with one or more (several) of the preferences for the aspects of the invention and/or other disclosures made herein.

The variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition may have a plasma half-life that is either longer or shorter, preferably longer, than the plasma half-life than a corresponding albumin or a fragment thereof or fusion polypeptides comprising albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition or a binding to FcRn that is stronger or weaker, preferably weaker. Preferably the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition has a plasma half-life that is longer than the plasma half-life of HSA or the corresponding albumin or a fragment thereof or fusion polypeptides comprising albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition.

Alternatively, this may be expressed as the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition having a KD to FcRn (e.g. shFcRn) that is lower than the corresponding KD for HSA to FcRn or the corresponding fragment thereof or fusion polypeptide comprising HSA or fragment thereof. Preferably, the KD for the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition is less than 0.9×KD for HSA to FcRn, more preferred less than 0.5×KD for HSA to FcRn, more preferred less than 0.1×KD for HSA to FcRn, even more preferred less than 0.05×KD for HSA to FcRn, even more preferred less than 0.02×KD for HSA to FcRn and most preferred less than 0.01×KD for HSA to FcRn (where X means ‘multiplied by’). The KD of the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition may be between the KD of WT albumin (e.g. SEQ ID No. 2) for FcRn and the KD of HSA K573P (SEQ ID No. 3) for FcRn. Such KDs represent binding affinities that are higher than the binding affinity between HSA and FcRn. A higher binding affinity indicates a longer half-life, for example plasma half-life.

Alternatively, the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition has a plasma half-life that is shorter than the plasma half-life of HSA or the corresponding fragment thereof or fusion polypeptide comprising HSA or fragment thereof.

This may be expressed as the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition having a KD to FcRn that is higher than the corresponding KD for HSA to FcRn or the corresponding of albumin or a fragment thereof or fusion polypeptides comprising albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition. Preferably, the KD for the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, or a conjugate comprising a variant of albumin or a fragment thereof is more than 2×KD for HSA to FcRn, more preferred more than 5×KD for HSA to FcRn, more preferred more than 10×KD for HSA to FcRn, even more preferred more than 25×KD for HSA to FcRn, most preferred more than 50×KD, more than 60×, more than 70×KD, more than 80×, more than 90× or more than 100×KD for HSA to FcRn. The variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition may be a null binder to FcRn.

The variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, or a conjugate or nanoparticle or associate or composition comprising a variant of albumin or a fragment thereof is preferably the variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, or a conjugate or nanoparticle or associate or composition comprising a variant of albumin or a fragment thereof according to the invention. A lower binding affinity indicates a shorter half-life, for example plasma half-life.

One advantage of the invention is that it allows the half-life of albumin, a variant of albumin or a fragment thereof or fusion polypeptides comprising variant albumin or fragments thereof, fragment thereof, conjugate, nanoparticle, associate or composition to be tailored in order to achieve a binding affinity or half-life which meets the needs of the user.

When determining and/or comparing KD, one or more (and preferably all) of the following parameters may be used:

Instrument: Biacore 3000 instrument (GE Healthcare)

Flow cell: CM5 sensor chip

FcRn: human FcRn, preferably soluble human FcRn, optionally coupled to a tag such as GST or His, most preferably His such as 6 histidines at the C-terminus of the beta-2-microglobulin (SEQ ID NO: 31).

Quantity of FcRn: 1200-2500 RU

Coupling chemistry: amine coupling chemistry (e.g. as described in the protocol provided by the manufacturer of the instrument).

Coupling method: The coupling may be performed by injecting 20 μg/ml of the protein in 10 mM sodium acetate pH 5.0 (GE Healthcare). Phosphate buffer (67 mM phosphate buffer, 0.15 M NaCl, 0.005% Tween 20) at pH 5.5) may be used as running buffer and dilution buffer. Regeneration of the surfaces may be done using injections of HBS-EP buffer (0.01 M HEPES, 0.15 M NaCl, 3 mM EDTA, 0.005% surfactant P20) at pH 7.4 (Biacore AB).

Quantity of injection of test molecule (e.g. HSA or variant) 20-0.032 μM

Flow rate of injection: constant, e.g. 30 μl/ml

Temperature of injection: 25° C.

Data evaluation software: BIAevaluation 4.1 software (BIAcore AB)

The preferred method for determining KD is provided in Example 2.

The invention discloses that two or more positions selected among the group consisting of positions 492, 550, 573, 574 and 580 in SEQ ID NO: 2 (and therefore equivalent positions in albumins and fragments from human serum and albumin and non-human serum albumins) may be altered in order to modulate (increase of decrease) the binding affinity and/or half-life e.g. plasma half-life of an albumin, fragment, fusion, conjugate, associate, nanoparticle or composition. An alteration may be a substitution, insertion or deletion. Substitution is preferred.

A substitution or insertion may or may not comprise introduction of a conserved amino acid, i.e. conserved in relation to the amino acid at the position of interest. Examples of conserved amino acids are shown by the groups of FIG. 3: aliphatic, aromatic, hydrophobic, charged, polar, positive, tiny and small. At position 492 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to G, D, F, H, M or R, even more preferred to G or D and most preferred to G. In SEQ ID NO: 2 the native amino acid at position 492 is E, therefore a substitution to E is not preferred.

At position 550 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to K, L, M, E or R, even more preferred to K, L or M and most preferred to K. In SEQ ID NO: 2 the native amino acid at position 550 is D, therefore a substitution to D is not preferred.

At position 573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to P, Y, W, H, F, T, I or V, even more preferred to P, Y or W and most preferred to P. In SEQ ID NO: 2 the native amino acid at position 573 is K, therefore a substitution to K is not preferred.

At position 574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to D, F, G, H, N, S or Y, even more preferred to H, D, F or G and most preferred to H. In SEQ ID NO: 2 the native amino acid at position 574 is K, therefore a substitution to K is not preferred.

At position 580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof), it is preferred that the alteration is a substitution, such as from the native amino acid to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, more preferred to K or R, most preferred to K. In SEQ ID NO: 2 the native amino acid at position 580 is Q, therefore a substitution to Q is not preferred.

A variant albumin may comprise alterations at positions corresponding to positions 492+550 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K (e.g. SEQ ID NO: 231), or 492G+550K (e.g. SEQ ID NO: 240).

A variant albumin may comprise alterations at positions corresponding to positions 492+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492F+573P (e.g. SEQ ID NO: 109), 492G+573P (e.g. SEQ ID NO: 110), 492H+573P (e.g. SEQ ID NO: 111) or 492R+573P (e.g. SEQ ID NO: 113) or more preferably 492D+573P (e.g. SEQ ID NO: 108). However, it is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations 492G+K573A, E492G+K573A, E492G+N503K+K573A, E492G+N503H+K573A, E492G+K573P, E492G+N503K+K573P or E492G+N503H+K573P.

A variant albumin may comprise alterations at positions corresponding to positions 492+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+574H (e.g. SEQ ID NO: 232), 492G+574H (e.g. SEQ ID NO: 241) or 492D+574H (e.g. SEQ ID NO: 232).

A variant albumin may comprise alterations at positions corresponding to positions 492+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 550+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise D550K+K573P (e.g. SEQ ID NO: 117).

A variant albumin may comprise alterations at positions corresponding to positions 550+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+574H (e.g. SEQ ID NO: 130), 550M+574H (e.g. SEQ ID NO: 249), 550M+574H (e.g. SEQ ID NO: 249) or 550L+574H (e.g. SEQ ID NO: 245).

A variant albumin may comprise alterations at positions corresponding to positions 550+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+580K (e.g. SEQ ID NO: 131), 550M+580K (e.g. SEQ ID NO: 251) or 550L+580K (e.g. SEQ ID NO: 247).

A variant albumin may comprise alterations at positions corresponding to positions 573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 574D+573P (e.g. SEQ ID NO: 121), 574F+573P (e.g. SEQ ID NO: 122), 574G+573P (e.g. SEQ ID NO: 123), 574H+573P (e.g. SEQ ID NO: 124), 574N+573P (e.g. SEQ ID NO: 125) or 5745+573P (e.g. SEQ ID NO: 126). It is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations K573P+K574N+A577T+A578R+5579C+Q580K+A581D+G584A.

A variant albumin may comprise alterations at positions corresponding to positions 573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 580K+573P (e.g. SEQ ID NO: 128) or 580R+573P (e.g. SEQ ID NO: 129). However, it is preferred that the variant does not consist of SEQ ID NO: 2 with only alterations K573P+A577E+A578S+Q580K+A582T.

A variant albumin may comprise alterations at positions corresponding to positions 574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492G+550K+573P (e.g. SEQ ID NO: 254) or 492D+550K+573P (e.g. SEQ ID NO: 253).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise E492G+D550K+K574H (e.g. SEQ ID NO: 255).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+580K (e.g. SEQ ID NO: 258) or 492G+550K+580K (e.g. SEQ ID NO: 259).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+574H (e.g. SEQ ID NO: 233).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+580K (e.g. SEQ ID NO: 234) or 492G+573P+580K (e.g. SEQ ID NO: 242).

A variant albumin may comprise alterations at positions corresponding to positions 492+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+574H+580K (SEQ ID NO: 262) or 492G+574H+580K (e.g. SEQ ID NO: 263).

A variant albumin may comprise alterations at positions corresponding to positions 550+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+574H+573P (e.g. SEQ ID NO: 131), 550L+573P+574H (e.g. SEQ ID NO: 246) or 550M+573P+574H (e.g. SEQ ID NO: 250).

A variant albumin may comprise alterations at positions corresponding to positions 550+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550L+573P+580K (e.g. SEQ ID NO: 248) or 550M+573P+580K (e.g. SEQ ID NO: 252).

A variant albumin may comprise alterations at positions corresponding to positions 550+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 574H+580K+573P (e.g. SEQ ID NO: 135).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+574 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492G+550K+573P+574H (e.g. SEQ ID NO: 257) or 492D+550K+573P+574H (e.g. SEQ ID NO: 256).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+573P+580K (e.g. SEQ ID NO: 260) or 492G+550K+573P+580K (e.g. SEQ ID NO: 261).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof).

A variant albumin may comprise alterations at positions corresponding to positions 492+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+573P+574H+580K (e.g. SEQ ID NO: 114) or 492G+573P+574H+580K (e.g. SEQ ID NO: 115), 492F+573P+574G+580K (e.g. SEQ ID NO: 238), 492G+573P+574G+580K (e.g. SEQ ID NO: 234), 492D+573P+574G+580K (e.g. SEQ ID NO: 235), 492F+573P+574H+580R (e.g. SEQ ID NO: 239), 492D+573P+574H+580K (e.g. SEQ ID NO: 264), 492G+573P+574H+580R (e.g. SEQ ID NO: 244), 492D+573P+574H+580R (e.g. SEQ ID NO: 236) or 492F+573P+574H+580K (e.g. SEQ ID NO: 237).

A variant albumin may comprise alterations at positions corresponding to positions 550+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 550K+573P+574H+580K (e.g. SEQ ID NO: 265).

A variant albumin may comprise alterations at positions corresponding to positions 492+550+573+574+580 of SEQ ID NO: 2 (or equivalent position of other albumins or variants or fragments thereof). Such alterations may comprise 492D+550K+573P+574H+580K (e.g. SEQ ID NO: 266) or 492G+550K+573P+574H+580K (e.g. SEQ ID NO: 267). Such alterations may comprise 492D+550K+573P+574H (e.g. SEQ ID NO: 256).

Particularly preferred variants include:

a variant albumin comprising alterations at positions corresponding to positions 492 and 580 in SEQ ID NO: 2, such as (i) E492G and Q580K, or (ii) E492D and Q580K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492 and 574 in SEQ ID NO: 2, such as (i) E492G and K574H, (ii) E492D and K574H, (iii) E492D and K574K, or (iv) E492G and K574K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492 and 550 in SEQ ID NO: 2, such as (i) E492G and D550K, or (ii) E492D and D550K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 573 in SEQ ID NO: 2, such as (i) D550K and K573P, (ii) D550L and K573P or (iii) D550M and K573P (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 574 in SEQ ID NO: 2, such as (i) D550K and K574H, or (ii) D550L and K574H (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 550 and 580 in SEQ ID NO: 2, such as (i) D550M and Q580K, (ii) D550L and Q580K or (iii) D550K and Q580K (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 580 and 573 in SEQ ID NO: 2, such as Q580K and K573P (or equivalent positions of other albumins or variants or fragment thereof) and preferably one or more (several) other alterations such at a position selected from 492, 550 and 574. If there is a K at position 580 and a P at position 573 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 574.

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 492 and 573 in SEQ ID NO: 2, such as a variant albumin comprising alterations at positions corresponding to positions 492 and 573 in SEQ ID NO: 2, such as (i) E492D and K573P or (ii) E492G and K573P or (iii) E492G and K573A (or equivalent positions of other albumins or variants or fragment thereof), and preferably one or more (several) other alterations such at a position selected from 550, 574 and 580. If there is a G at position 492 and an A or P at position 573 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 550, 574 and 580 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin with alterations (e.g. comprising alterations) at positions corresponding to positions 573 and 574 in SEQ ID NO: 2, such as K573P and K574H (or equivalent positions of other albumins or variants or fragment thereof, and preferably one or more (several) alterations such as at a position selected from 492, 550 and 580. If there is a P at position 573 and an N at position 574 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 580 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 574 and 580 in SEQ ID NO: 2, such as 574H and 580K (or equivalent positions of other albumins or variants or fragment thereof. If there is a N at position 574 and a K at position 580 it is preferred that the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 573 (or equivalent positions of other albumins or variants or fragment thereof);

a variant albumin comprising alterations at positions corresponding to positions 492, 550 and 573 in SEQ ID NO: 2, such as E492G, D550K and K573P e.g. SEQ ID NO: 254 or such as E492D, D550K and K573P e.g. SEQ ID NO: 253;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 580 in SEQ ID NO: 2, such as D550K, K573P and Q580K e.g. SEQ ID NO: 133;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 580 in SEQ ID NO: 2, such as D550L, K573P and Q580K e.g. SEQ ID NO: 248 or such as D550M, K573P and Q580K e.g. SEQ ID NO:252;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 574 in SEQ ID NO: 2, such as D550L, K573P and K574H e.g. SEQ ID NO:246;

a variant albumin comprising alterations at positions corresponding to positions 550, 573 and 574 in SEQ ID NO: 2, such as D550K, K573P and K574H e.g. SEQ ID NO: 131;

a variant albumin comprising alterations at positions corresponding to positions 492, 573 and 580 in SEQ ID NO: 2, such as E492G, K573P and Q580K e.g. SEQ ID NO: 242;

a variant albumin comprising alterations at positions corresponding to positions 492, 573 and 580 in SEQ ID NO: 2, such as E492D, K573P and Q580K e.g. SEQ ID NO: 234;

a variant albumin comprising alterations at positions corresponding to positions 492, 550, 573 and 574 in SEQ ID NO: 2, such as E492D, D550K, K573P and K574H e.g. SEQ ID NO: 256;

a variant albumin comprising alterations at positions corresponding to positions 492, 550, 573 and 574 in SEQ ID NO: 2, such as E492G, D550K, K573P and K574H e.g. SEQ ID NO: 257;

a variant albumin comprising alterations at positions corresponding to positions 573, 574 and 580 in SEQ ID NO: 2, such as K573P, K574H and Q580K e.g. SEQ ID NO: 135;

a variant albumin comprising alterations at positions corresponding to positions 492, 573, 574 and 580 in SEQ ID NO: 2, such as E492D, K573P, K574H and Q580K (or equivalent positions of other albumins or variants or fragment thereof), e.g. SEQ ID NO: 114;

a variant albumin comprising alterations at positions corresponding to positions 492, 573, 574 and 580 in SEQ ID NO: 2, such as E492G, K573P, K574H and Q580K (or equivalent positions of other albumins or variants or fragment thereof), e.g. SEQ ID NO: 115.

It is preferred that the alteration at position 492 is conserved relative to D or E. It is preferred that the alteration at position 574 is conserved relative to H. It is preferred that the alteration at position 580 is conserved relative to K.

Advantageously, the polypeptide retains substantially the same tertiary structure (or, for a fragment, the relevant part of the structure) as a reference or parent albumin such as HSA. The skilled person understand the term ‘substantially the same tertiary structure’ bearing in mind that some degree of variation in tertiary structure is expected as all proteins have some degree of structural flexibility. This applies particularly to polypeptides having a higher binding affinity to FcRn than the parent or reference albumin (e.g. HSA) has to FcRn.

One or more (several) of the His residues may or may not be maintained relative to the parent albumin. For example, with reference to SEQ ID NO: 2, one or more (several) of the following His residues may be maintained: 3, 9, 39, 67, 105, 128, 146, 242, 247, 288, 338, 367, 440, 464, 510, 535. One or more (several), preferably all, of the His residues in domain I are maintained (i.e. 3, 9, 39, 67, 105, 128, 146.). One or more (several), preferably all, of the His residues in domain II are maintained (i.e. 242, 247, 288, 338, 367). One or more (several), preferably all, of the His residues in domain III are maintained (i.e. 440, 464, 510, 535). One or more (several) or all three of His 464, 510, 535 may be maintained.

It is preferred that at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 of the disulphide bonds of the albumin are maintained in the polypeptide. For a polypeptide derived from a full length albumin, it is preferred that all disulphide bonds usually present in that albumin are maintained. For a polypeptide derived from a fragment of albumin, it is preferred that all disulphide bonds usually present in that fragment are maintained. It is preferred that Cys34 (or equivalent in non-human albumins) is maintained.

For all aspects of the invention fusion partner polypeptides and/or conjugates may comprise one or more (several) of: 4-1BB ligand, 5-helix, A human C-C chemokine, A human L105 chemokine, A human L105 chemokine designated huL105_3., A monokine induced by gamma-interferon (MIG), A partial CXCR4B protein, A platelet basic protein (PBP), α1-antitrypsin, ACRP-30 Homologue; Complement Component C1q C, Adenoid-expressed chemokine (ADEC), aFGF; FGF-1, AGF, AGF Protein, albumin, an etoposide, angiostatin, Anthrax vaccine, Antibodies specific for collapsin, antistasin, Anti-TGF beta family antibodies, antithrombin III, APM-1; ACRP-30; Famoxin, apo-lipoprotein species, Arylsulfatase B, b57 Protein, BCMA, Beta-thromboglobulin protein (beta-TG), bFGF; FGF2, Blood coagulation factors, BMP Processing Enzyme Furin, BMP-10, BMP-12, BMP-15, BMP-17, BMP-18, BMP-2B, BMP-4, BMP-9, Bone Morphogenic Protein-2, calcitonin, Calpain-10a, Calpain-10b, Calpain-10c, Cancer Vaccine, Carboxypeptidase, C-C chemokine, MCP2, CCR5 variant, CCR7, CCR7, CD11a Mab, CD137; 4-1BB Receptor Protein, CD20 Mab, CD27, CD27L, CD30, CD30 ligand, CD33 immunotoxin, CD40, CD40L, CD52 Mab, Cerebus Protein, Chemokine Eotaxin., Chemokine hIL-8, Chemokine hMCP1, Chemokine hMCP1a, Chemokine hMCP1b, Chemokine hMCP2, Chemokine hMCP3, Chemokine hSDF1b, Chemokine MCP-4, chemokine TECK and TECK variant, Chemokine-like protein IL-8M1 Full-Length and Mature, Chemokine-like protein IL-8M10 Full-Length and Mature, Chemokine-like protein IL-8M3, Chemokine-like protein IL-8M8 Full-Length and Mature, Chemokine-like protein IL-8M9 Full-Length and Mature, Chemokine-like protein PF4-414 Full-Length and Mature, Chemokine-like protein PF4-426 Full-Length and Mature, Chemokine-like protein PF4-M2 Full-Length and Mature, Cholera vaccine, Chondromodulin-like protein, c-kit ligand; SCF; Mast cell growth factor; MGF; Fibrosarcoma-derived stem cell factor, CNTF and fragment thereof (such as CNTFAx15′(Axokine™)), coagulation factors in both pre and active forms, collagens, Complement C5 Mab, Connective tissue activating protein-III, CTAA16.88 Mab, CTAP-III, CTLA4-Ig, CTLA-8, CXC3, CXC3, CXCR3; CXC chemokine receptor 3, cyanovirin-N, Darbepoetin, designated exodus, designated huL105_7., DIL-40, DNase, EDAR, EGF Receptor Mab, ENA-78, Endostatin, Eotaxin, Epithelial neutrophil activating protein-78, EPO receptor; EPOR, erythropoietin (EPO) and EPO mimics, Eutropin, Exodus protein, Factor IX, Factor VII, Factor VIII, Factor X and Factor XIII, FAS Ligand Inhibitory Protein (DcR3), FasL, FasL, FasL, FGF, FGF-12; Fibroblast growth factor homologous factor-1, FGF-15, FGF-16, FGF-18, FGF-3; INT-2, FGF-4; gelonin, HST-1; HBGF-4, FGF-5, FGF-6; Heparin binding secreted transforming factor-2, FGF-8, FGF-9; Glia activating factor, fibrinogen, flt-1, fit-3 ligand, Follicle stimulating hormone Alpha subunit, Follicle stimulating hormone Beta subunit, Follitropin, Fractalkine, fragment. myofibrillar protein Troponin I, FSH, Galactosidase, Galectin-4, G-CSF, GDF-1, Gene therapy, Glioma-derived growth factor, glucagon, glucagon-like peptides, Glucocerebrosidase, glucose oxidase, Glucosidase, Glycodelin-A; Progesterone-associated endometrial protein, GM-CSF, gonadotropin, Granulocyte chemotactic protein-2 (GCP-2), Granulocyte-macrophage colony stimulating factor, growth hormone, Growth related oncogene-alpha (GRO-alpha), Growth related oncogene-beta (GRO-beta), Growth related oncogene-gamma (GRO-gamma), hAPO-4; TROY, hCG, Hepatitus B surface Antigen, Hepatitus B Vaccine, HER2 Receptor Mab, hirudin, HIV gp120, HIV gp41, HIV Inhibitor Peptide, HIV Inhibitor Peptide, HIV Inhibitor Peptide, HIV protease inhibiting peptides, HIV-1 protease inhibitors, HPV vaccine, Human 6CKine protein, Human Act-2 protein, Human adipogenesis inhibitory factor, human B cell stimulating factor-2 receptor, Human beta-chemokine H1305 (MCP-2), Human C-C chemokine DGWCC, Human CC chemokine ELC protein, Human CC type chemokine interleukin C, Human CCC3 protein, Human CCF18 chemokine, Human CC-type chemokine protein designated SLC (secondary lymphoid chemokine), Human chemokine beta-8 short forms, Human chemokine C10, Human chemokine CC-2, Human chemokine CC-3, Human chemokine CCR-2, Human chemokine Ckbeta-7, Human chemokine ENA-78, Human chemokine eotaxin, Human chemokine GRO alpha, Human chemokine GROalpha, Human chemokine GRObeta, Human chemokine HCC-1, Human chemokine HCC-1, Human chemokine 1-309, Human chemokine IP-10, Human chemokine L105_3, Human chemokine L105_7, Human chemokine MIG, Human chemokine MIG-beta protein, Human chemokine MIP-1 alpha, Human chemokine MIP1beta, Human chemokine MIP-3alpha, Human chemokine MIP-3beta, Human chemokine PF4, Human chemokine protein 331D5, Human chemokine protein 61164, Human chemokine receptor CXCR3, Human chemokine SDF1alpha, Human chemokine SDF1beta, Human chemokine ZSIG-35, Human Chr19Kine protein, Human CKbeta-9, Human CKbeta-9, Human CX3C 111 amino acid chemokine, Human DNAX interleukin-40, Human DVic-1 C-C chemokine, Human EDIRF I protein sequence, Human EDIRF II protein sequence, Human eosinocyte CC type chemokine eotaxin, Human eosinophil-expressed chemokine (EEC), Human fast twitch skeletal muscle troponin C, Human fast twitch skeletal muscle troponin I, Human fast twitch skeletal muscle Troponin subunit C, Human fast twitch skeletal muscle Troponin subunit I Protein, Human fast twitch skeletal muscle Troponin subunit T, Human fast twitch skeletal muscle troponin T, Human foetal spleen expressed chemokine, FSEC, Human GM-CSF receptor, Human gro-alpha chemokine, Human gro-beta chemokine, Human gro-gamma chemokine, Human IL-16 protein, Human IL-1RD10 protein sequence, Human IL-1RD9, Human IL-5 receptor alpha chain, Human IL-6 receptor, Human IL-8 receptor protein hIL8RA, Human IL-8 receptor protein hIL8RB, Human IL-9 receptor protein, Human IL-9 receptor protein variant #3, Human IL-9 receptor protein variant fragment, Human IL-9 receptor protein variant fragment#3, Human interleukin 1 delta, Human Interleukin 10, Human Interleukin 10, Human interleukin 18, Human interleukin 18 derivatives, Human interleukin-1 beta precursor, Human interleukin-1 beta precursor., Human interleukin-1 receptor accessory protein, Human interleukin-1 receptor antagonist beta, Human interleukin-1 type-3 receptor, Human Interleukin-10 (precursor), Human Interleukin-10 (precursor), Human interleukin-11 receptor, Human interleukin-12 40 kD subunit, Human interleukin-12 beta-1 receptor, Human interleukin-12 beta-2 receptor, Human Interleukin-12 p35 protein, Human Interleukin-12 p40 protein, Human interleukin-12 receptor, Human interleukin-13 alpha receptor, Human interleukin-13 beta receptor, Human interleukin-15, Human interleukin-15 receptor from clone P1, Human interleukin-17 receptor, Human interleukin-18 protein (IL-18), Human interleukin-3, human interleukin-3 receptor, Human interleukin-3 variant, Human interleukin-4 receptor, Human interleukin-5, Human interleukin-6, Human interleukin-7, Human interleukin-7., Human interleukin-8 (IL-8), Human intracellular IL-1 receptor antagonist, Human IP-10 and HIV-1 gp120 hypervariable region fusion protein, Human IP-10 and human Muc-1 core epitope (VNT) fusion protein, human liver and activation regulated chemokine (LARC), Human Lkn-1 Full-Length and Mature protein, Human mammary associated chemokine (MACK) protein Full-Length and Mature, Human mature chemokine Ckbeta-7, Human mature gro-alpha, Human mature gro-gamma polypeptide used to treat sepsis, Human MCP-3 and human Muc-1 core epitope (VNT) fusion protein, Human MI10 protein, Human MI1A protein, Human monocyte chemoattractant factor hMCP-1, Human monocyte chemoattractant factor hMCP-3, Human monocyte chemotactic proprotein (MCPP) sequence, Human neurotactin chemokine like domain, Human non-ELR CXC chemokine H174, Human non-ELR CXC chemokine IP10, Human non-ELR CXC chemokine Mig, Human PAI-1 mutants, Human protein with IL-16 activity, Human protein with IL-16 activity, Human secondary lymphoid chemokine (SLC), Human SISD protein, Human STCP-1, Human stromal cell-derived chemokine, SDF-1, Human T cell mixed lymphocyte reaction expressed chemokine (TMEC), Human thymus and activation regulated cytokine (TARC), Human thymus expressed, Human TNF-alpha, Human TNF-alpha, Human TNF-beta (LT-alpha), Human type CC chemokine eotaxin 3 protein sequence, Human type II interleukin-1 receptor, Human wild-type interleukin-4 (hIL-4) protein, Human ZCHEMO-8 protein, Humanized Anti-VEGF Antibodies, and fragments thereof, Humanized Anti-VEGF Antibodies, and fragments thereof, Hyaluronidase, ICE 10 kD subunit., ICE 20 kD subunit., ICE 22 kD subunit., Iduronate-2-sulfatase, Iduronidase, IL-1 alpha, IL-1 beta, IL-1 inhibitor (IL-1i)., IL-1 mature, IL-10 receptor, IL-11, IL-11, IL-12 p40 subunit., IL-13, IL-14, IL-15, IL-15 receptor, IL-17, IL-17 receptor, II-17 receptor, II-17 receptor, IL-19, IL-1i fragments, IL1-receptor antagonist, IL-21 (TIF), IL-3 containing fusion protein., IL-3 mutant proteins, IL-3 variants, IL-3 variants, IL-4, IL-4 mutein, IL-4 mutein Y124G, IL-4 mutein Y124X, IL-4 muteins, 11-5 receptor, IL-6, 11-6 receptor, IL-7 receptor clone, IL-8 receptor, IL-9 mature protein variant (Met117 version), immunoglobulins or immunoglobulin-based molecules or fragment of either (e.g. a Small Modular ImmunoPharmaceutical™ (“SMIP”) or dAb, Fab′ fragments, F(ab′)2, scAb, scFv or scFv fragment), including but not limited to plasminogen, Influenza Vaccine, Inhibin alpha, Inhibin beta, insulin, insulin-like growth factor, Integrin Mab, inter-alpha trypsin inhibitor, inter-alpha trypsin inhibitor, Interferon gamma-inducible protein (IP-10), interferons (such as interferon alpha species and sub-species, interferon beta species and sub-species, interferon gamma species and sub-species), interferons (such as interferon alpha species and sub-species, interferon beta species and sub-species, interferon gamma species and sub-species), Interleukin 6, Interleukin 8 (IL-8) receptor, Interleukin 8 receptor B, Interleukin-1alpha, Interleukin-2 receptor associated protein p43, interleukin-3, interleukin-4 muteins, Interleukin-8 (IL-8) protein., interleukin-9, Interleukin-9 (IL-9) mature protein (Thr117 version), interleukins (such as IL10, IL11 and IL2), interleukins (such as IL10, IL11 and IL2), Japanese encephalitis vaccine, Kalikrein Inhibitor, Keratinocyte growth factor, Kunitz domain protein (such as aprotinin, amyloid precursor protein and those described in WO 03/066824, with or without albumin fusions), Kunitz domain protein (such as aprotinin, amyloid precursor protein and those described in WO 03/066824, with or without albumin fusions), LACI, lactoferrin, Latent TGF-beta binding protein II, leptin, Liver expressed chemokine-1 (LVEC-1), Liver expressed chemokine-2 (LVEC-2), LT-alpha, LT-beta, Luteinization Hormone, Lyme Vaccine, Lymphotactin, Macrophage derived chemokine analogue MDC (n+1), Macrophage derived chemokine analogue MDC-eyfy, Macrophage derived chemokine analogue MDC-yl, Macrophage derived chemokine, MDC, Macrophage-derived chemokine (MDC), Maspin; Protease Inhibitor 5, MCP-1 receptor, MCP-1a, MCP-1b, MCP-3, MCP-4 receptor, M-CSF, Melanoma inhibiting protein, Membrane-bound proteins, Met117 human interleukin 9, MIP-3 alpha, MIP-3 beta, MIP-Gamma, MIRAP, Modified Rantes, monoclonal antibody, MP52, Mutant Interleukin 6 S176R, myofibrillar contractile protein Troponin I, Natriuretic Peptide, Nerve Growth Factor-beta, Nerve Growth Factor-beta2, Neuropilin-1, Neuropilin-2, Neurotactin, Neurotrophin-3, Neurotrophin-4, Neurotrophin-4a, Neurotrophin-4b, Neurotrophin-4c, Neurotrophin-4d, Neutrophil activating peptide-2 (NAP-2), NOGO-66 Receptor, NOGO-A, NOGO-B, NOGO-C, Novel beta-chemokine designated PTEC, N-terminal modified chemokine GroHEK/hSDF-1 alpha, N-terminal modified chemokine GroHEK/hSDF-1beta., N-terminal modified chemokine met-hSDF-1 alpha, N-terminal modified chemokine met-hSDF-1 beta, OPGL, Osteogenic Protein-1; OP-1; BMP-7, Osteogenic Protein-2, OX40; ACT-4, OX40L, Oxytocin (Neurophysin I), parathyroid hormone, Patched, Patched-2, PDGF-D, Pertussis toxoid, Pituitary expressed chemokine (PGEC), Placental Growth Factor, Placental Growth Factor-2, Plasminogen Activator Inhibitor-1; PAI-1, Plasminogen Activator Inhibitor-2; PAI-2, Plasminogen Activator Inhibitor-2; PAI-2, Platelet derived growth factor, Platelet derived growth factor Bv-sis, Platelet derived growth factor precursor A, Platelet derived growth factor precursor B, Platelet Mab, platelet-derived endothelial cell growth factor (PD-ECGF), Platelet-Derived Growth Factor A chain, Platelet-Derived Growth Factor B chain, polypeptide used to treat sepsis, Preproapolipoprotein “milano” variant, Preproapolipoprotein “paris” variant, pre-thrombin, Primate CC chemokine “ILINCK”, Primate CXC chemokine “IBICK”, proinsulin, Prolactin, Prolactin2, prosaptide, Protease inhibitor peptides, Protein C, Protein S, pro-thrombin, prourokinase, RANTES, RANTES 8-68, RANTES 9-68, RANTES peptide, RANTES receptor, Recombinant interleukin-16, Resistin, restrictocin, Retroviral protease inhibitors, ricin, Rotavirus Vaccine, RSV Mab, saporin, sarcin, Secreted and Transmembrane polypeptides, Secreted and Transmembrane polypeptides, serum cholinesterase, serum protein (such as a blood clotting factor), Soluble BMP Receptor Kinase Protein-3, Soluble VEGF Receptor, Stem Cell Inhibitory Factor, Straphylococcus Vaccine, Stromal Derived Factor-1 alpha, Stromal Derived Factor-1 beta, Substance P (tachykinin), T1249 peptide, T20 peptide, T4 Endonuclease, TACI, Tarc, TGF-beta 1, TGF-beta 2, Thr117 human interleukin 9, thrombin, thrombopoietin, Thrombopoietin derivative1, Thrombopoietin derivative2, Thrombopoietin derivative3, Thrombopoietin derivative4, Thrombopoietin derivative5, Thrombopoietin derivative6, Thrombopoietin derivative7, Thymus expressed chemokine (TECK), Thyroid stimulating Hormone, tick anticoagulant peptide, Tim-1 protein, TNF-alpha precursor, TNF-R, TNF-RII; TNF p75 Receptor; Death Receptor, tPA, transferrin, transforming growth factor beta, Troponin peptides, Truncated monocyte chemotactic protein 2 (6-76), Truncated monocyte chemotactic protein 2 (6-76), Truncated RANTES protein (3-68), tumour necrosis factor, Urate Oxidase, urokinase, Vasopressin (Neurophysin II), VEGF R-3; flt-4, VEGF Receptor; KDR; flk-1, VEGF-110, VEGF-121, VEGF-138, VEGF-145, VEGF-162, VEGF-165, VEGF-182, VEGF-189, VEGF-206, VEGF-D, VEGF-E; VEGF-X, von Willebrand's factor, Wild type monocyte chemotactic protein 2, Wild type monocyte chemotactic protein 2, ZTGF-beta 9, alternative antibody scaffolds e.g. anticalin(s), adnectin(s), fibrinogen fragment(s), nanobodies such as camelid nanobodies, infestin, and/or any of the molecules mentioned in WO01/79271 (particularly page 9 and/or Table 1), WO 2003/59934 (particularly Table 1), WO03/060071 (particularly Table 1) or WO01/079480 (particularly Table 1) (each incorporated herein by reference in their entirety).

Furthermore, conjugates may comprise one or more (several) of chemotherapy drugs such as: 13-cis-Retinoic Acid, 2-CdA, 2-Chlorodeoxyadenosine, 5-Azacitidine, 5-Fluorouracil, 5-FU, 6-Mercaptopurine, 6-MP, 6-TG, 6-Thioguanine, A, Abraxane, Accutane®, Actinomycin-D, Adriamycin®, Adrucil®, Agrylin®, Ala-Cort®, Aldesleukin, Alemtuzumab, ALIMTA, Alitretinoin, Alkaban-AQ®, Alkeran®, All-transretinoic Acid, Alpha Interferon, Altretamine, Amethopterin, Amifostine, Aminoglutethimide, Anagrelide, Anandron®, Anastrozole, Arabinosylcytosine, Ara-C, Aranesp, Aredia®, Arimidex®, Aromasin, Arranon, Arsenic Trioxide, Asparaginase, ATRA, Avastin, Azacitidine, BCG, BCNU, Bevacizumab, Bexarotene, BEXXAR®, Bicalutamide, BiCNU, Blenoxane®, Bleomycin, Bortezomib, Busulfan, Busulfex®, C225, Calcium Leucovorin, Campath®, Camptosar®, Camptothecin-11, Capecitabine, Carac™ Carboplatin, Carmustine, Carmustine Wafer, Casodex®, CC-5013, CCNU, CDDP, CeeNU, Cerubidine Cetuximab, Chlorambucil, Cisplatin, Citrovorum Factor, Cladribine, Cortisone, Cosmegen®, CPT-11, Cyclophosphamide, Cytadren®, Cytarabine, Cytarabine Liposomal, Cytosar-U®, Cytoxan®, Dacarbazine, Dacogen, Dactinomycin, Darbepoetin Alfa, Dasatinib, Daunomycin, Daunorubicin, Daunorubicin Hydrochloride, Daunorubicin Liposomal, DaunoXome®, Decadron, Decitabine, Delta-Cortef®, Deltasone®, Denileukin diftitox, DepoCyt™, Dexamethasone, Dexamethasone acetate, Dexamethasone Sodium Phosphate, Dexasone, Dexrazoxane, DHAD, DIC, Diodex, Docetaxel, Doxorubicin, Doxorubicin liposomal, Droxia™, DTIC, DTIC-Dome®, Duralone®, Efudex®, Eligard™ Ellence™, Eloxatin™, Elspar®, Emcyt®, Epirubicin, Epoetin alfa, Erbitux™, Erlotinib, Erwinia L-asparaginase, Estramustine, Ethyol, Etopophos®, Etoposide, Etoposide Phosphate, Eulexin®, Evista®, Exemestane, Fareston®, Faslodex®, Femara®, Filgrastim, Floxuridine, Fludara®, Fludarabine, Fluoroplex®, Fluorouracil, Fluorouracil (cream), Fluoxymesterone, Flutamide, Folinic Acid, FUIDR®, Fulvestrant, G-CSF, Gefitinib, Gemcitabine, Gemtuzumab ozogamicin, Gemzar®, Gleevec™, Gliadel® Wafer, GM-CSF, Goserelin, Granulocyte—Colony Stimulating Factor, Granulocyte Macrophage Colony Stimulating Factor, Halotestin®, Herceptin®, Hexadrol, Hexalen®, Hexamethylmelamine, HMM, Hycamtin®, Hydrea®, Hydrocort Acetate®, Hydrocortisone, Hydrocortisone Sodium Phosphate, Hydrocortisone Sodium Succinate, Hydrocortone Phosphate, Hydroxyurea, Ibritumomab, Ibritumomab Tiuxetan, Idamycin®, Idarubicin, Ifex®, IFN-alpha, Ifosfamide, IL-11, IL-2, Imatinib mesylate, Imidazole Carboxamide, Interferon alfa, Interferon Alfa-2b (PEG Conjugate), Interleukin-2, Interleukin-11, Intron A® (interferon alfa-2b), Iressa®, Irinotecan, Isotretinoin, Kidrolase®, Lanacort®, Lapatinib, L-asparaginase, LCR, Lenalidomide, Letrozole, Leucovorin, Leukeran, Leukine™, Leuprolide, Leurocristine, Leustatin™ Liposomal Ara-C, Liquid Pred®, Lomustine, L-PAM, L-Sarcolysin, Lupron®, Lupron Depot®, M, Matulane®, Maxidex, Mechlorethamine, Mechlorethamine Hydrochloride, Medralone®, Medrol®, Megace®, Megestrol, Megestrol Acetate, Melphalan, Mercaptopurine, Mesna, Mesnex™, Methotrexate, Methotrexate Sodium, Methylprednisolone, Meticorten®, Mitomycin, Mitomycin-C, Mitoxantrone, M-Prednisol®, MTC, MTX, Mustargen®, Mustine, Mutamycin®, Myleran®, Mylocel™, Mylotarg®, Navelbine®, Nelarabine, Neosar®, Neulasta™, Neumega®, Neupogen®, Nexavar®, Nilandron®, Nilutamide, Nipent®, Nitrogen Mustard, Novaldex®, Novantrone®, Octreotide, Octreotide acetate, Oncospar®, Oncovin®, Ontak®, Onxal™, Oprevelkin, Orapred®, Orasone®, Oxaliplatin, a taxol or taxol derivative e.g. Paclitaxel or Paclitaxel Protein-bound, Pamidronate, Panitumumab, Panretin®, Paraplatin®, Pediapred®, PEG Interferon, Pegaspargase, Pegfilgrastim, PEG-INTRON™ PEG-L-asparaginase, PEMETREXED, Pentostatin, Phenylalanine Mustard, Platinol®, Platinol-AQ®, Prednisolone, Prednisone, Prelone®, Procarbazine, PROCRIT®, Proleukin®, Prolifeprospan 20 with Carmustine Implant, Purinethol®, R, Raloxifene, Revlimid®, Rheumatrex®, Rituxan®, Rituximab, RoferonA® (Interferon Alfa-2a), Rubex®, Rubidomycin hydrochloride, Sandostatin °, Sandostatin LAR®, Sargramostim, Solu-Cortef®, SoluMedrol®, Sorafenib, SPRYCEL™, STI-571, Streptozocin, SU11248, Sunitinib, Sutent®, Tamoxifen, Tarceva®, Targretin®, Taxol®, Taxotere®, Temodar®, Temozolomide, Teniposide, TESPA, Thalidomide, Thalomid®, TheraCys®, Thioguanine, Thioguanine Tabloid®, Thiophosphoamide, Thioplex®, Thiotepa, TICE®, Toposar®, Topotecan, Toremifene, Tositumomab, Trastuzumab, Tretinoin, Trexall™, Trisenox®, TSPA, TYKERB®, VCR, Vectibix™, Velban®, Velcade®, VePesid®, Vesanoid®, Viadur™, Vidaza®, Vinblastine, Vinblastine Sulfate, Vincasar Pfs®, Vincristine, Vinorelbine, Vinorelbine tartrate, VLB, VM-26, Vorinostat, VP-16, Vumon®, Xeloda®, Zanosar®, Zevalin™, Zinecard®, Zoladex®, Zoledronic acid, Zolinza, Zometa®; radiopharmaceuticals such as: Carbon-11, Carbon-14, Chromium-51, Cobalt-57, Cobalt-58, Erbium-169, Fluorine-18, Gallium-67, Gold-198, Indium-111, Indium-113m, Iodine-123, Iodine-125, Iodine-131, Iron-59, Krypton-81m, Nitrogen-13, Oxygen-15, Phosphorous-32, Rhenium-186, Rubidium-82, Samarium-153, Selenium-75, Strontium-89, Technetium-99m, Thallium-201, Tritium, Xenon-127, Xenon-133, Yttrium-90; imaging agents such as Gadolinium, magnetite, manganese, technetium, I125, I131, P32, TI201, Iopamidol, PET-FDG.

Further fusion partners, conjugation partners and/or molecules for inclusion in a nanoparticle, associate or composition according to the invention include: acromegaly drugs e.g. somatuline, lanreotide, octreotide, Sandostatin; antithrombotics e.g. bivalirudin, Angiomax, dalteparin, Fragmin, enoxaparin, Lovenox, Drotrecogin alfa (e.g. Activated), Xigris, heparin; assisted reproductive therapy compounds e.g. choriogonadotropin, Ovidrel, follitropin, alpha/beta; enzymes e.g. hyaluronidase, Hylenex; diabetes drugs e.g. exenatide, Byetta, glucagon, insulin, liraglutide, albiglutide, GLP-1 agonists, exendin or an exendin analog; compounds useful in diagnosis e.g. protirelin, Thyrel TRH Thypinone, secretin (e.g. synthetic human), Chirhostim, thyrotropin (e.g. alpha), Thyrogen′ erythropoiesis drugs e.g. Darbepoetin alfa, Aranesp, Epoetin alfa, Epogen, Eprex, drugs for the treatment of genetic defects e.g. pegademase, drugs for the treatment of growth failure e.g. Adagen, mecasermin, rinfabate, drugs for the treatment of cystic fibrosis e.g. Dornase alfa, Pulmozyme, drugs for the treatment of metaoblic disorders e.g. Agalsidase beta, Fabrazyme, alglucosidase alpha, Myozyme, Laronidase, Aldurazyme, drugs for the treatment of genital wart intralesional e.g. Interferon alfa-n3, Alferon N, drugs for the treatment of granulomatous disease e.g. Interferon gamma-1b, Actimmune; drugs for the treatment of growth failure e.g. pegvisomant, Somavert, somatropin, Genotropin, Nutropin, Humatrope, Serostim, Protropin; drugs for the treatment of heart failure e.g. nesiritide, Natrecor; drugs for the treatment of hemophilia e.g. a coagulation factor e.g. Factor VIII, Helixate FS, Kogenate FS, Factor IX, BeneFIX, Factor VIIa, Novoseven, desmopressin, Stimate, DDAVP; hemopoetic drugs e.g. Filgrastim (G-CSF), Neupogen, Oprelvekin, Neumega, Pegfilgrastim, Neulasta, Sargramostim, Leukine; drugs for the treatment of hepatitis C e.g. Interferon alfa-2a, Roferon A, Interferon alfa-2b, Intron A, Interferon alfacon-1, Infergen, Peginterferon alfa-2a, Pegasys, Peginterferon alfa-2b, PEG-Intron; drugs for the treatment of HIV e.g. enfuvirtide, Fuzeon; Fabs e.g. Fab (antithrombin), Abciximab, ReoPro; monoclonal antibodies e.g. Daclizumab, Zenapax; antiviral monoclonal antibodies e.g. Palivizumab, Synagis; monoclonal antibodies for the treatment of asthma e.g. Omalizumab, Xolair; monoclonal antibodies for use in diagnostic imaging e.g. Arcitumomab, CEA-Scan, Capromab Pendetide, ProstaScint, Satumomab Pendetide, OncoScint CR/OV, Fabs for use in diagnostic imaging e.g. Nofetumomab, Verluma; iimmuno-supressant monoclonal antibodies e.g. Basiliximab, Simulect, Muromonab-CD3, Orthoclone OKT3; monoclonal antibodies for the treatment of malignancy e.g. Alemtuzumab, Campath, Ibritumomab tiuxetan, Zevalin, Rituximab, Rituxan, Trastuzumab, Herceptin; monoclonal antibodies for the treatment of rheumatoid arthritis (RA) e.g. Adalimumab, Humira, Infliximab, Remicade; monoclonal antibodies for use as a radio-immuno-therapeutic e.g. Tositumomab and Iodine I¹³¹, Tositumomab, Bexxar; drugs for the treatment of macular degeneration e.g. pegaptanib, Macugen; drugs for the treatment of malignancy e.g. Aldesleukin, Proleukin, Interleukin-2, Asparaginase, Elspar, Rasburicase, Elitek, Denileukin diftitox, Ontak, Pegaspargase, Oncaspar, goserelin, leuprolide; drugs for the treatment of multiple sclerosis (MS) e.g. Glatiramer acetate (e.g. copolymer-1), Copaxone, Interferon beta-1a, Avonex, Interferon beta-1a, Rebif, Interferon beta-1b, Betaseron; drugs for the treatment of mucositis e.g. palifermin, Kepivance; drug for the treatment of dystonia e.g., neurotoxin, Botulinum Toxin Type A, BOTOX, BOTOX Cosmetic, Botulinum Toxin Type B, MYOBLOC; drugs for the treatment of osteoporosis e.g. teriparatide, Forteo; drugs for the treatment of psoriasis e.g. Alefacept, Amevive; drugs for the treatment of RA e.g. abatacept, Orencia, Anakinra, Kineret, Etanercept, Enbrel; thrombolytics e.g. Alteplase, Activase, rtPA, Anistreplase, Eminase, Reteplase, Retavase, Streptokinase, Streptase, Tenecteplase, TNKase, Urokinase, Abbokinase, Kinlytic; drugs for the treatment of osteoporosis e.g. calcitonin (e.g. salmon), Miacalcin, Fortical, drugs for the treatment of skin ulcers e.g. Becaplermin, Regranex, Collagenase, Santyl.

Such polypeptides and chemical compounds may be referred to as diagnostic moieties, therapeutic moieties, prophylactic moieties or beneficial moieties.

Preferably the fusion partner and/or conjugation partner is not an albumin, variant or fragment thereof.

One or more (several) therapeutic or prophylactic polypeptides may be fused to the N-terminus, the C-terminus of albumin, inserted into a loop in the albumin structure or any combination thereof. It may or it may not comprise linker sequences separating the various components of the fusion polypeptide.

Teachings relating to fusions of albumin or a fragment thereof are known in the art and the skilled person will appreciate that such teachings can also be applied to the invention. WO 2001/79271A and WO 2003/59934 (incorporated herein by reference) also contain examples of therapeutic and prophylactic polypeptides that may be fused to albumin or fragments thereof, and these examples apply also to the invention.

The invention is further defined in the following embodiments:

1. A polypeptide which is a variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or a fragment thereof having an altered binding affinity to FcRn compared with the binding affinity of a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof to FcRn, wherein the polypeptide comprises alterations at two or more positions selected from positions corresponding to positions 492, 550, 573, 574 and 580 in SEQ ID NO: 2.

2. The polypeptide according to embodiment 1 wherein the polypeptide comprises alterations at two or more positions selected from positions corresponding to positions (a) 492 and 580; (b) 492 and 574; (c) 492 and 550; (d) 550 and 573; (e) 550 and 574; (f) 550 and 580 in SEQ ID NO: 2.

3. The polypeptide according to embodiment 1 or 2 comprising alterations at positions corresponding to positions 492 and 580 of SEQ ID NO: 1, further comprising one or more (several) alterations at positions corresponding to positions selected from the group consisting of 550, 573 and 574 of SEQ ID NO: 2.

4. The polypeptide according to embodiment 1, 2 or 3 comprising alterations at positions corresponding to positions 492 and 574 of SEQ ID NO: 1, further comprising one or more (several) alterations at positions corresponding to positions selected from the group consisting 550, 573 and 580 of SEQ ID NO:

5. The polypeptide according to any preceding embodiment comprising alterations at positions corresponding to positions 492 and 550 of SEQ ID NO: 1, further comprising one or more (several) alterations at positions corresponding to positions selected from the group consisting 573, 574 and 580 of SEQ ID NO: 2.

6. The polypeptide according to any preceding embodiment comprising alterations at positions corresponding to positions 550 and 573 of SEQ ID NO: 1, further comprising one or more (several) alterations at positions corresponding to positions selected from the group consisting 492, 574, and 580 of SEQ ID NO: 2.

7. The polypeptide according to any preceding embodiment comprising alterations at positions corresponding to positions 550 and 574 of SEQ ID NO: 1, further comprising one or more (several) alterations at positions corresponding to positions selected from the group consisting 492, 573 and 580 of SEQ ID NO: 2.

8. The polypeptide according to any preceding embodiment comprising alterations at positions corresponding to positions 550 and 580 of SEQ ID NO: 1, further comprising an alteration at a position corresponding to position 492, 573 and 574 of SEQ ID NO: 2.

9. The polypeptide according to any preceding embodiment in which:

(a) at a position corresponding to position 492 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of A, C, D, F, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y, preferably D and at a position corresponding to position 573 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H, or

(b) at a position corresponding to position 492 of SEQ ID NO: 2 there is an alteration to generate G and at a position corresponding to position 573 there is an alteration to generate A or P and the polypeptide comprises an additional alteration at a position selected from the group consisting of 550, 574 and 580 (or equivalent positions of other albumins or variants or fragment thereof).

10. The polypeptide according to any preceding embodiment in which:

(a) at a position corresponding to position 573 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H and at a position corresponding to position 574 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, P, Q, R, S, T, V, W, Y, H, D, F, G, N, S or Y, more preferably H, D, F or G, most preferably H, or

(b) at a position corresponding to position 573 of SEQ ID NO: 2 there is a P and at a position corresponding to position 574 of SEQ ID NO: 2 there is an N and the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 580 (or equivalent positions of other albumins or variants or fragment thereof);

11. The polypeptide according to any preceding embodiment in which:

(a) at a position corresponding to position 573 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, Q, R, S, T, V, W, Y, preferably Y, W or H and at a position corresponding to position 580 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of C, D, E, F, G, H, I, L, M, N, P, R, S, T, V, W, Y, or

(b) at a position corresponding to position 573 of SEQ ID NO: 2 there is an alteration to generate a P and at a position corresponding to position 580 of SEQ ID NO: 2 there is an alteration to generate a K and the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 574 (or equivalent positions of other albumins or variants or fragment thereof).

12. The polypeptide according to any preceding embodiment in which:

(a) at a position corresponding to position 574 of SEQ ID NO: 2 there is an alteration to generate an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, P, Q, R, S, T, V, W, Y, H, D, F, G, N, S or Y, more preferably H, D, F or G, most preferably H and at a position corresponding to position 580 of SEQ ID NO: 2 there is an alteration to generate at a position corresponding to position to an amino acid from the group consisting of A, C, D, E, F, G, H, I, L, M, N, P, R, S, T, V, W, Y, or

(b) at a position corresponding to position 574 of SEQ ID NO: 2 there is an alteration to generate an N and at a position corresponding to position 580 of SEQ ID NO: 2 there is an alteration to generate a K and the polypeptide comprises an additional alteration at a position selected from the group consisting of 492, 550, and 573 (or equivalent positions of other albumins or variants or fragment thereof).

13. The polypeptide according to any preceding embodiment, wherein the polypeptide comprises alterations at three or more positions selected from positions corresponding to positions 492, 550, 573, 574 and 580 in SEQ ID NO: 2.

14. The polypeptide according to any preceding embodiment wherein the alteration at the position corresponding to position 492, 550, 573, 574 and/or 580 is a substitution.

15. The polypeptide of embodiment 14 wherein the substitution at the position corresponding to position 492 is to G, D, F, H, M or R.

16. The polypeptide of embodiment 14 or 15 wherein the substitution at the position corresponding to position 492 is to G or D.

17. The polypeptide of any of embodiments 13 to 15 wherein the substitution at the position corresponding to position 492 is to G.

18. The polypeptide of any of embodiments 13 to 15 wherein the substitution at the position corresponding to position 492 is to D.

19. The polypeptide of any of embodiments 13 to 18 wherein the substitution at the position corresponding to position 550 is to K, L, M E, or R.

20. The polypeptide of any of embodiments 13 to 19 wherein the substitution at the position corresponding to position 550 is to K, L or M.

21. The polypeptide of any of embodiments 13 to 20 wherein the substitution at the position corresponding to position 550 is to K.

22. The polypeptide of any of embodiments 13 to 21 wherein the alteration at the position corresponding to position 573 is a substitution to P, Y, W, H, F, T, I or V.

23. The polypeptide of any of embodiments 13 to 22 wherein the substitution at the position corresponding to position 573 is to P, Y or W.

24. The polypeptide of any of embodiments 13 to 23 wherein the substitution at the position corresponding to position 573 is to a P.

25. The polypeptide of any of embodiments 13 to 24 wherein the alteration at the position corresponding to position 574 is a substitution to H, G, D, F, N, S or Y.

26. The polypeptide of any of embodiments 13 to 25 wherein the substitution at the position corresponding to position 574 is to D, F, G or H.

27. The polypeptide of any of embodiments 13 to 26 wherein the substitution at the position corresponding to position 574 is to H.

28. The polypeptide of any of embodiments 13 to 27 wherein the substitution at the position corresponding to position 580 is to K or R.

29. The polypeptide of any of embodiments 13 to 28 wherein the substitution at the position corresponding to position 580 is to K.

30. The polypeptide of any preceding embodiment wherein the polypeptide comprises alterations at positions corresponding to positions (i) 573 and 580; (ii) 492 and 573; or (iii) 573 and 574 of SEQ ID NO: 2.

31. The polypeptide of any preceding embodiment wherein the polypeptide comprises alterations at two or more positions corresponding to the following positions of SEQ ID NO: 2: 580K+573P (e.g. SEQ ID NO: 128); 580R+573P (e.g. SEQ ID NO: 129); 574D+573P (e.g. SEQ ID NO: 121); 574F+573P (e.g. SEQ ID NO: 122); 574G+573P (e.g. SEQ ID NO: 123); 574H+573P (e.g. SEQ ID NO: 124); 574N+573P (e.g. SEQ ID NO: 125); 5745+573P (e.g. SEQ ID NO: 126); 550K+580K (e.g. SEQ ID NO: 132); 550K+574H (e.g. SEQ ID NO: 130); 550K+573P (e.g. SEQ ID NO: 117); 492D+573P (e.g. SEQ ID NO: 108); 492F+573P (e.g. SEQ ID NO: 109); 492H+573P (e.g. SEQ ID NO: 111); 492R+573P (e.g. SEQ ID NO: 112); 574H+580K (e.g. SEQ ID NO: 134); 550L+574H (e.g. SEQ ID NO: 245); 550L+580K (e.g. SEQ ID NO: 247); 550M+580K (e.g. SEQ ID NO: 251); 492D+550K (e.g. SEQ ID NO: 231); 550M+574H (e.g. SEQ ID NO: 249); 492D+574H (e.g. SEQ ID NO: 232); 492G+550K (e.g. SEQ ID NO: 240); 550M+574H (e.g. SEQ ID NO: 249); or 492G+574H (e.g. SEQ ID NO: 241).

32. The polypeptide according to any preceding embodiment wherein the polypeptide comprises three or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

33. The polypeptide of embodiment 32 wherein the polypeptide comprises alterations at positions corresponding to the following positions of SEQ ID NO: 2: 574H+580K+573P (e.g. SEQ ID NO: 135); 550K+574H+573P (e.g. SEQ ID NO: 131); 492D+550K+573P (e.g. SEQ ID NO: 253); 550M+573P+580K (e.g. SEQ ID NO: 252); 550L+573P+580K (e.g. SEQ ID NO: 253); 492G+573P+580K (e.g. SEQ ID NO: 242); 550M+573P+574H (e.g. SEQ ID NO: 250); 492G+550K+573P (e.g. SEQ ID NO: 254); 550L+573P+574H (e.g. SEQ ID NO: 246); 492D+573P+580K (e.g. SEQ ID NO: 234); 492D+573P+574H (e.g. SEQ ID NO: 233); 492G+574H+580K (e.g. SEQ ID NO: 263); 492G+550K+580K (e.g. SEQ ID NO: 259); 492D+550K+580K (e.g. SEQ ID NO: 258); 492D+574H+580K (e.g. SEQ ID NO: 262); or 492G+550K+574H (e.g. SEQ ID NO: 255).

34. The polypeptide according to any preceding embodiment wherein the polypeptide comprises four or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

35. The polypeptide of embodiment 34 wherein the polypeptide comprises alterations at positions corresponding to the following positions of SEQ ID NO: 2: 492G+573P+574H+580K (e.g. SEQ ID NO: 115); 492D+573P+574H+580K (e.g. SEQ ID NO: 114); 550K+573P+574H+580K (e.g. SEQ ID NO: 265); 492G+550K+573P+580K (e.g. SEQ ID NO: 261); 492F+573P+574H+580K (e.g. SEQ ID NO: 237); 492G+573P+574G+580K (e.g. SEQ ID NO: 243); 492D+573P+574H+580R (e.g. SEQ ID NO: 236); 492G+573P+574H+580R (e.g. SEQ ID NO: 244); 492D+550K+573P+580K (e.g. SEQ ID NO: 260); 492D+550K+573P+574H (e.g. SEQ ID NO: 256); 492F+573P+574H+580R (e.g. SEQ ID NO: 239); 492D+573P+574G+580K (e.g. SEQ ID NO: 235); or 492F+573P+574G+580K (e.g. SEQ ID NO: 238).

36. The polypeptide according to any preceding embodiment wherein the polypeptide comprises five or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

37. The polypeptide according to embodiment wherein the polypeptide comprises alterations at positions corresponding to the following positions of SEQ ID NO: 2: 492G+550K+573P+574H+580K (e.g. SEQ ID NO: 267) or 492D+550K+573P+574H+580K (e.g. SEQ ID NO: 266).

38. The polypeptide according to any preceding embodiment comprising alterations corresponding to the following positions in SEQ ID NO: 2: 492G+573P+574H+580K (e.g. SEQ ID NO: 115); 492G+550K+573P+574H (e.g. SEQ ID NO: 257); 492D+550K+573P+574H (e.g. SEQ ID NO: 256); 492G+550K+573P (e.g. SEQ ID NO: 254); 492D+550K+573P (e.g. SEQ ID NO: 253); 550M+573P+580K (e.g. SEQ ID NO: 252); 550L+573P+580K (e.g. SEQ ID NO: 248); 550L+573P+574H (e.g. SEQ ID NO: 246); 492G+573P+580K (e.g. SEQ ID NO: 242); 492D+573P+580K (e.g. SEQ ID NO: 234); 573P+574H+580K (e.g. SEQ ID NO: 135); 550K+573P+580K (e.g. SEQ ID NO: 133); 550K+573P+574H (e.g. SEQ ID NO: 131); or 492D+573P+574H+580K (SEQ ID NO: 114).

39. The polypeptide of any of embodiments 1 to 38 wherein the reference albumin is HSA (SEQ ID No: 2) or a fragment thereof, or a fusion polypeptide comprising HSA or a fragment thereof, most preferably SEQ ID NO: 2.

40. The polypeptide according to any of embodiments 1 to 39, having a stronger binding affinity to FcRn and/or longer plasma half-life than a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof.

41. The polypeptide according any of embodiments 1 to 40, wherein the sequence identity of the polypeptide to SEQ ID NO: 2 is more than 80%, preferably more than 90%, more preferred more than 95%, more preferred more than 96%, even more preferred more than 97%, more preferred more than 98% and most preferred more than 99%.

42. A fusion polypeptide comprising a polypeptide according to any of embodiments 1 to 41 and a fusion partner polypeptide selected from a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

43. A method for preparing a polypeptide which is a variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof having a binding affinity to FcRn which is altered compared to the binding affinity of a reference albumin, fragment or fusion thereof to FcRn, comprising:

(a) Providing a nucleic acid encoding a parent albumin having at least 80% sequence identity to SEQ ID NO: 2;

(b) Modifying the sequence of step (a), to encode a polypeptide which is a variant albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof comprising alterations at two or more positions corresponding to positions selected from 492, 550, 573, 574 and 580 in SEQ ID NO: 2, preferably as described in any of embodiments 1 to 13;

(c) Introducing the modified sequence of step (b) in a suitable host cell;

(d) Growing the cells in a suitable growth medium under condition leading to expression of the polypeptide; and

(e) Recovering the polypeptide from the growth medium;

wherein the polypeptide has an altered binding affinity to FcRn and/or an altered plasma half-life compared with the half-life of a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof.

44. The method of embodiment 43 wherein the substitution at the position corresponding to position 492 is a substitution to G, D, F, H, M or R, preferably G or D

45. The method of embodiment 44 wherein the substitution at the position corresponding to position 492 is to G.

46. The method of embodiment 44 wherein the substitution at the position corresponding to position 492 is to D.

47. The method of any of embodiments 43 to 46 wherein the substitution at the position corresponding to position 550 is to K, L, M, E or R, preferably K, L or M, most preferably K.

48. The method of any of embodiments 43 to 47 wherein the substitution at the position corresponding to position 573 is a substitution to P, Y, W, H, F, T, I or V, preferably P, Y, or W, most preferably P.

49. The method of any of embodiments 43 to 48 wherein the substitution at the position corresponding to position 574 is a substitution to H, D, F, G, N, S or Y, preferably H, D, F, or G, most preferably H.

50. The method of any of embodiments any of embodiments 43 to 49 wherein the substitution at the position corresponding to position 580 is a substitution to K or R, most preferably R.

51. The method of any of embodiments 43 to 50 wherein the two or more alterations are at positions corresponding to positions (i) 573 and 580; (ii) 492 and 573; or

(iii) 573 and 574 of SEQ ID NO: 2.

52. The method according to any of embodiments 43 to 51 wherein the two or more alterations are at positions corresponding to the following positions of SEQ ID NO: 2: 580K+573P (e.g. SEQ ID NO: 128); 580R+573P (e.g. SEQ ID NO: 129); 574D+573P (e.g. SEQ ID NO: 121); 574F+573P (e.g. SEQ ID NO: 122); 574G+573P (e.g. SEQ ID NO: 123); 574H+573P (e.g. SEQ ID NO: 124); 574N+573P (e.g. SEQ ID NO: 125); 5745+573P (e.g. SEQ ID NO: 126); 550K+580K (e.g. SEQ ID NO: 132); 550K+574H (e.g. SEQ ID NO: 130); 550K+573P (e.g. SEQ ID NO: 117); 492D+573P (e.g. SEQ ID NO: 108); 492F+573P (e.g. SEQ ID NO: 109); 492H+573P (e.g. SEQ ID NO: 111); 492R+573P (e.g. SEQ ID NO: 112); 574H+580K (e.g. SEQ ID NO: 134); 550L+574H (e.g. SEQ ID NO: 245); 550L+580K (e.g. SEQ ID NO: 247); 550M+580K (e.g. SEQ ID NO: 251); 492D+550K (e.g. SEQ ID NO: 231); 550M+574H (e.g. SEQ ID NO: 249); 492D+574H (e.g. SEQ ID NO: 232); 492G+550K (e.g. SEQ ID NO: 240); 550M+574H (e.g. SEQ ID NO: 249); or 492G+574H (e.g. SEQ ID NO: 241).

53. The method according to any of embodiments 43 to 52 comprising three or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

54. The method according to any of embodiments 43 to 53 comprising alterations at positions corresponding to the following positions of SEQ ID NO: 2: 574H+580K+573P (e.g. SEQ ID NO: 135); 550K+574H+573P (e.g. SEQ ID NO: 131); 492D+550K+573P (e.g. SEQ ID NO: 253); 550M+573P+580K (e.g. SEQ ID NO: 252); 550L+573P+580K (e.g. SEQ ID NO: 253); 492G+573P+580K (e.g. SEQ ID NO: 242); 550M+573P+574H (e.g. SEQ ID NO: 250); 492G+550K+573P (e.g. SEQ ID NO: 254); 550L+573P+574H (e.g. SEQ ID NO: 246); 492D+573P+580K (e.g. SEQ ID NO: 234); 492D+573P+574H (e.g. SEQ ID NO: 233); 492G+574H+580K (e.g. SEQ ID NO: 263); 492G+550K+580K (e.g. SEQ ID NO: 259); 492D+550K+580K (e.g. SEQ ID NO: 258); 492D+574H+580K (e.g. SEQ ID NO: 262); or 492G+550K+574H (e.g. SEQ ID NO: 255).

55. The method according to any of embodiments 43 to 54 comprising four or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

56. The method according to any of embodiments 43 to 55 comprising alterations at positions corresponding to the following positions of SEQ ID NO: 2: 492G+573P+574H+580K (e.g. SEQ ID NO: 115); 492D+573P+574H+580K (e.g. SEQ ID NO: 114); 550K+573P+574H+580K (e.g. SEQ ID NO: 265); 492G+550K+573P+580K (e.g. SEQ ID NO: 261); 492F+573P+574H+580K (e.g. SEQ ID NO: 237); 492G+573P+574G+580K (e.g. SEQ ID NO: 243); 492D+573P+574H+580R (e.g. SEQ ID NO: 236); 492G+573P+574H+580R (e.g. SEQ ID NO: 244); 492D+550K+573P+580K (e.g. SEQ ID NO: 260); 492D+550K+573P+574H (e.g. SEQ ID NO: 256); 492F+573P+574H+580R (e.g. SEQ ID NO: 239); 492D+573P+574G+580K (e.g. SEQ ID NO: 235); or 492F+573P+574G+580K (e.g. SEQ ID NO: 238).

57. The method according to any of embodiments 43 to 56 comprising five or more alterations at positions selected from the group consisting of positions corresponding to the following positions of SEQ ID NO: 2: 492, 550, 573, 574 and 580.

58. The polypeptide according to any of embodiments 43 to 57 comprising alterations at positions corresponding to the following positions of SEQ ID NO: 2: 492G+550K+573P+574H+580K (e.g. SEQ ID NO: 267) or 492D+550K+573P+574H+580K (e.g. SEQ ID NO: 266).

59. The method according to any of embodiments 43 to 58 comprising alterations at positions corresponding to the following positions in SEQ ID NO: 2: 492G+573P+574H+580K (e.g. SEQ ID NO: 115); 492G+550K+573P+574H (e.g. SEQ ID NO: 257); 492D+550K+573P+574H (e.g. SEQ ID NO: 256); 492G+550K+573P (e.g. SEQ ID NO: 254); 492D+550K+573P (e.g. SEQ ID NO: 253); 550M+573P+580K (e.g. SEQ ID NO: 252); 550L+573P+580K (e.g. SEQ ID NO: 248); 550L+573P+574H (e.g. SEQ ID NO: 246); 492G+573P+580K (e.g. SEQ ID NO: 242); 492D+573P+580K (e.g. SEQ ID NO: 234); 573P+574H+580K (e.g. SEQ ID NO: 135); 550K+573P+580K (e.g. SEQ ID NO: 133); 550K+573P+574H (e.g. SEQ ID NO: 131); or 492D+573P+574H+580K (SEQ ID NO: 114).

60. The method any of embodiments 43 to 59 wherein the reference albumin is HSA (SEQ ID No: 2) or a fragment thereof, or a fusion polypeptide comprising HSA or a fragment thereof, most preferably SEQ ID NO: 2.

61. The method according any of embodiments 43 to 60, wherein the sequence identity of the polypeptide to SEQ ID NO: 2 is more than 80%, preferably more than 90%, more preferred more than 95%, more preferred more than 96%, even more preferred more than 97%, more preferred more than 98% and most preferred more than 99%.

62. A conjugate comprising a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61 and a conjugation partner.

63. The conjugate according to embodiment 62 wherein the conjugation partner is a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

64. An associate comprising a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61 and a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

65. A nanoparticle or microparticle comprising a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61, a conjugate according to embodiment 62 or 63 or an associate according to embodiment 64.

66. A composition comprising a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61, a conjugate according to embodiment 62 or 63, an associate according to embodiment 64 or a nanoparticle or microparticle according embodiment 65, wherein the binding affinity of the polypeptide, fusion polypeptide, conjugate, associate or nanoparticle or microparticle to FcRn is stronger than the binding affinity of a composition comprising the corresponding parent albumin, reference albumin, fragment thereof or fusion polypeptide, conjugate, associate or nanoparticle or microparticle comprising said parent albumin, reference albumin or fragment or fusion thereof to FcRn.

67. A composition according to embodiment 66 where the binding affinity of the polypeptide, fusion polypeptide, conjugate, associate or nanoparticle or microparticle to FcRn is stronger than the binding affinity of HSA to FcRn.

68. A composition according to embodiment 66 or 67, wherein the binding coefficient of the variant of the polypeptide, fusion polypeptide, conjugate, associate or nanoparticle or microparticle to FcRn is less than 0.9×KD of HSA to FcRn, more preferred less than 0.5×KD of HSA to FcRn, more preferred less than 0.1×KD of HSA to FcRn, even more preferred less than 0.05×KD of HSA to FcRn, even more preferred less than 0.02×KD of HSA to FcRn and most preferred less than 0.01×KD of HSA to FcRn.

69. The composition according to any of embodiments 66 to 68, comprising a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61, a conjugate according to embodiment 62 or 63, an associate according to embodiment 64 or a nanoparticle or microparticle according embodiment 65, further comprising a compound comprising an antibody binding domain (ABD) and a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

70. The composition according to any of embodiments 66 to 69, comprising a pharmaceutically acceptable carrier or excipient.

71. Use of a polypeptide according to any of embodiments 1 to 42 or obtainable by a method according to any of embodiments 43 to 61, a conjugate according to embodiment 62 or 63, an associate according to embodiment 64 or a nanoparticle or microparticle according embodiment 65 or a composition according to any of embodiments 66 to 70 to alter the binding affinity to FcRn or half-life, preferably in plasma, of a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

72. The use according to embodiment 71 wherein the binding affinity to FcRn is increased relative to the binding affinity of a reference comprising or consisting of HSA (SEQ ID NO: 2) or a fragment, fusion, conjugate, associate, nanoparticle or microparticle thereof to FcRn.

73. The use according to embodiment 71 wherein the binding affinity to FcRn is decreased relative to the binding affinity of a reference comprising or consisting of HSA (SEQ ID NO: 2) or a fragment, fusion, conjugate, associate, nanoparticle or microparticle thereof to FcRn.

74. A method for altering the binding affinity to FcRn or half-life preferably in plasma, of a molecule comprising:

(a) where the molecule is a polypeptide, fusing or conjugating the molecule to a polypeptide according to any of embodiments 1 to 42 or obtainable by a method of embodiments 43 to 61, or to a conjugate according to embodiment 62 or 63; associating the molecule to a polypeptide according to any of embodiments 1 to 42 or obtainable by a method of embodiments 43 to 61 or to a conjugate according to embodiment 62 or 63; incorporating the molecule in an associate according to embodiment 64, in nanoparticle or microparticle according to embodiment 65 or a composition according to any of embodiments 66 to 70;

(b) where the molecule is not a polypeptide, conjugating the molecule to a polypeptide according to any of embodiments 1 to 42 or obtainable by a method of embodiments 43 to 61, or to a conjugate according to embodiment 62 or 63; associating the molecule to a polypeptide according to any of embodiments 1 to 42 or obtainable by a method of embodiments 43 to 61 or to a conjugate according to embodiment 62 or 63; incorporating the molecule in an associate according to embodiment 64, in nanoparticle or microparticle according to embodiment 65 or a composition according to any of embodiments 66 to 70.

75. A method according to embodiment 74 wherein the molecule is a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.

76. A polypeptide, fusion polypeptide, conjugate, associate, nanoparticle or microparticle or composition thereof according to any of embodiments 1 to 42 or 62 to 70 or obtainable by the method of embodiments 43 to 61 wherein the polypeptide, fusion polypeptide, conjugate, associate, nanoparticle or microparticle or composition comprises one or more (several) moiety selected from those described herein.

77. A nucleic acid encoding the polypeptide or fusion polypeptide of any of embodiments 1 to 76.

78. A vector comprising a nucleic acid according to embodiment 77.

79. A host cell comprising a nucleic acid according to embodiment 77 or a vector according to embodiment 78.

80. A host cell according to embodiment 79 wherein the host cell is a eukaryote, preferably a yeast (such as Saccharomyces cerevisiae) or a mammalian cell (such as CHO or HEK) or a plant cell (such as rice).

81. A method of prophylaxis, treatment or diagnosis comprising administering a polypeptide, fusion polypeptide, conjugate, composition, associate, nanoparticle or microparticle or polynucleotide according to any of embodiments 1 to 42 or 62 to 70 or obtainable by the method of any of embodiments 43 to 61 to a subject.

The invention is further described by the following examples that should not be construed as limiting the scope of the invention.

EXAMPLES Example 1: Preparation of HSA Variant Expression Plasmids for HSA

HSA variants were expressed using standard molecular biology techniques, such as described in Sambrook, J. and D. W. Russell, 2001 (Molecular Cloning: a laboratory manual, 3^(rd) ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y).

Method 1:

Permutation libraries at positions E492, D550, K574H and Q580K were produced by PCR amplification of pDB4081, encoding wild type HSA (described below), using a mutagenic forward primer and non-mutagenic reverse primer as shown in Table 2. The PCR conditions are shown in Tables 3 and 4. 2 μl of reaction product was assessed by agarose gel electrophoresis and the remainder treated with 5 μl of 10× buffer 4 (New England Biolabs—50 mM potassium acetate, 20 mM Tris-acetate, 10 mM magnesium acetate, 1 mM DTT pH 7.9 at 25° C.) and 1 μl DpnI (NEB) for 1 hour at 37° C. The reactions were purified by addition of 50 μl water, prior to application of a vacuum for 20 minutes. A further 50 μl of water was added and a vacuum applied until the well was dry. Plasmid DNA was recovered by addition of 30 μl of water and incubation for 1 minute. 2 μl of this purified product was transformed into 15 μl TOP10 E. coli cells by standard protocols. Clones were selected and grown overnight in LB supplemented with 100 μg/ml ampicillin and purified using a Qiagen QIAprep 96 miniprep kit according to manufacturer's instructions. Variants were verified by sequencing.

pDB4081 was made by the ligation of a synthetic DNA fragment, BsaI/SphI digested, which had been generated by gene assembly (DNA2.0 Inc, USA), containing 3′ region of the PRB1 promoter, modified fusion leader sequence, nucleotide sequence encoding HSA and 5′ region of the modified ADH1 terminator) into HindIII/SphI-digested pDB4005. pDB4005 is described in WO 2011/051489 (incorporated herein by reference).

TABLE 2 Plasmid and amino acid substitution and relevant primers Variant SEQ ID Oligo1 Oligo 2 Plasmid Variant No. (SEQ ID No.) (SEQ ID No.) name HSA E492A 32 HSA-1 (136) REV E492 (212) pDB4768 HSA E492C 33 HSA-2 (137) REV E492 (212) pDB4769 HSA E492D 34 HSA-3 (138) REV E492 (212) pDB4770 HSA E492F 35 HSA-4 (139) REV E492 (212) pDB4771 HSA E492G 36 HSA-5 (140) REV E492 (212) pDB4772 HSA E492H 37 HSA-6 (141) REV E492 (212) pDB4773 HSA E492I 38 HSA-7 (142) REV E492 (212) pDB4774 HSA E492K 39 HSA-8 (143) REV E492 (212) pDB4775 HSA E492L 40 HSA-9 (144) REV E492 (212) pDB4776 HSA E492M 41 HSA-10 (145) REV E492 (212) pDB4777 HSA E492N 42 HSA-11 (146) REV E492 (212) pDB4778 HSA E492P 43 HSA-12 (147) REV E492 (212) pDB4779 HSA E492Q 44 HSA-13 (148) REV E492 (212) pDB4780 HSA E492R 45 HSA-14 (149) REV E492 (212) pDB4781 HSA E492S 46 HSA-15 (150) REV E492 (212) pDB4782 HSA E492T 47 HSA-16 (151) REV E492 (212) pDB4783 HSA E492V 48 HSA-17 (152) REV E492 (212) pDB4784 HSA E492W 49 HSA-18 (153) REV E492 (212) pDB4785 HSA E492Y 50 HSA-19 (154) REV E492 (212) pDB4856 HSA D550A 51 HSA-20 (155) REV D550 (213) pDB4786 HSA D550C 52 HSA-21 (156) REV D550 (213) pDB4857 HSA D550E 53 HSA-22 (157) REV D550 (213) pDB4858 HSA D550F 54 HSA-23 (158) REV D550 (213) pDB4859 HSA D550G 55 HSA-24 (159) REV D550 (213) pDB4787 HSA D550H 56 HSA-25 (160) REV D550 (213) pDB4788 HSA D550I 57 HSA-26 (161) REV D550 (213) pDB4789 HSA D550K 58 HSA-27 (162) REV D550 (213) pDB4790 HSA D550L 59 HSA-28 (163) REV D550 (213) pDB4791 HSA D550M 60 HSA-29 (164) REV D550 (213) pDB4792 HSA D550N 61 HSA-30 (165) REV D550 (213) pDB4793 HSA D550P 62 HSA-31 (166) REV D550 (213) pDB4794 HSA D550Q 63 HSA-32 (167) REV D550 (213) pDB4795 HSA D550R 64 HSA-33 (168) REV D550 (213) pDB4796 HSA D550S 65 HSA-34 (169) REV D550 (213) pDB4797 HSA D550T 66 HSA-35 (170) REV D550 (213) pDB4798 HSA D550V 67 HSA-36 (171) REV D550 (213) pDB4799 HSA D550Y 68 HSA-37 (172) REV D550 (213) pDB4800 HSA D550W 69 HSA-38 (173) REV D550 (213) pDB4801 HSA K574A 70 HSA-39 (174) REV K574 (214) pDB4802 HSA K574C 71 HSA-40 (175) REV K574 (214) pDB4803 HSA K574D 72 HSA-41 (176) REV K574 (214) pDB4804 HSA K574E 73 HSA-42 (177) REV K574 (214) pDB4805 HSA K574F 74 HSA-43 (178) REV K574 (214) pDB4806 HSA K574G 75 HSA-44 (179) REV K574 (214) pDB4807 HSA K574H 76 HSA-45 (180) REV K574 (214) pDB4808 HSA K574I 77 HSA-46 (181) REV K574 (214) pDB4809 HSA K574L 78 HSA-47 (182) REV K574 (214) pDB4810 HSA K574M 79 HSA-48 (183) REV K574 (214) pDB4811 HSA K574N 80 HSA-49 (184) REV K574 (214) pDB4812 HSA K574P 81 HSA-50 (185) REV K574 (214) pDB4813 HSA K574Q 82 HSA-51 (186) REV K574 (214) pDB4814 HSA K574R 83 HSA-52 (187) REV K574 (214) pDB4815 HSA K574S 84 HSA-53 (188) REV K574 (214) pDB4816 HSA K574T 85 HSA-54 (189) REV K574 (214) pDB4817 HSA K574V 86 HSA-55 (190) REV K574 (214) pDB4818 HSA K574Y 87 HSA-56 (191) REV K574 (214) pDB4819 HSA K574W 88 HSA-57 (192) REV K574 (214) pDB4820 HSA Q580A 89 HSA-58 (193) REV Q580 (215) pDB4821 HSA Q580C 90 HSA-59 (194) REV Q580 (215) pDB4822 HSA Q580D 91 HSA-60 (195) REV Q580 (215) pDB4823 HSA Q580E 92 HSA-61 (196) REV Q580 (215) pDB4824 HSA Q580F 93 HSA-62 (197) REV Q580 (215) pDB4825 HSA Q580G 94 HSA-63 (198) REV Q580 (215) pDB4826 HSA Q580H 95 HSA-64 (199) REV Q580 (215) pDB4827 HSA Q580I 96 HSA-65 (200) REV Q580 (215) pDB4828 HSA Q580K 97 HSA-66 (201) REV Q580 (215) pDB4829 HSA Q580L 98 HSA-67 (202) REV Q580 (215) pDB4830 HSA Q580M 99 HSA-68 (203) REV Q580 (215) pDB4831 HSA Q580N 100 HSA-69 (204) REV Q580 (215) pDB4832 HSA Q580P 101 HSA-70 (205) REV Q580 (215) pDB4833 HSA Q580R 102 HSA-71 (206) REV Q580 (215) pDB4834 HSA Q58OS 103 HSA-72 (207) REV Q580 (215) pDB4835 HSA Q580T 104 HSA-73 (208) REV Q580 (215) pDB4836 HSA Q580V 105 HSA-74 (209) REV Q580 (215) pDB4837 HSA Q580Y 106 HSA-75 (210) REV Q580 (215) pDB4838 HSA Q580W 107 HSA-76 (211) REV Q580 (215) pDB4839

TABLE 3 PCR reaction components *HF buffer (5x) 10 μl template DNA 1 μl (20 ng/μl) dNTP (2.5 mM) 5 μl *Phusion 0.5 μl (polymerase) oligo 1 (20 μM) 1 μl dH₂O 31.5 μl oligo 2 (20 μM) 1 μl (*HF buffer and Phusion polymerase are from New England Biolabs)

TABLE 4 PCR reaction conditions Temperature Cycle length Number of cycles 98° C. 3 min 1 98° C. 15 sec 30 65° C. 35 sec 72° C. 11 min 72° C. 11 min 1

Method 2:

Variants described in Table 5 and 6 were produced as described in WO2012/150319, Example 6, Method 2 ‘Production of combination Variants with K573P’ (incorporated herein by reference), with the following modifications. For variants shown in Table 5, a fragment encoding the K573P mutation was removed from pDB4673 via the SalI and Bsu36I restriction sites and inserted into similarly digested parent plasmid, as indicated in Table 5. pDB4673 (HSA K573P) was constructed by insertion of the fragment produced by digestion of pD4283 (described in WO 2011/051489, incorporated herein by reference) with SalI and HinDIII restriction enzymes into similarly digested pDB4081. For variants shown in Table 6, the fragment encoding K573P+K574H+Q580K was removed from pDB5032 using the SalI and Bsu36I restriction sites and inserted into similarly digested parent plasmid, as indicated in Table 6.

TABLE 5 Plasmid and amino acid substitution Variant Relevant SEQ ID Parent Plasmid Variant No. Plasmid name HSA E492D + K573P 108 pDB4770 pDB4990 HSA E492F + K573P 109 pDB4771 pDB4991 HSA E492G + K573P 110 pDB4772 pDB4992 HSA E492H + K573P 111 pDB4773 pDB4993 HSA E492M + K573P 112 pDB4777 pDB4994 HSA E492R + K573P 113 pDB4781 pDB4995

TABLE 6 Plasmid and amino acid substitution Variant Relevant SEQ ID Parent Plasmid Variant No. Plasmid name HSA E492D + K573P + 114 pDB4770 pDB5091 K574H + Q580K HSA E492G + K573P + 115 pDB4772 pDB5092 K574H + Q580K

Method 3:

Variants described in Table 7 were produced as described in WO2012/150319, Example 6, Method 1 (incorporated herein by reference), using the plasmids indicated in the tables as templates for the PCR reactions. The conditions described in Tables 8 and 9 were used to produce pDB4997-5004, pDB 5042-46, and pDB5030-1. Those described in Tables 10 and 11 were used to produce pDB5027-29 and pDB5032. The mutated PCR products were digested using SalI and Bsu36I restriction enzymes and inserted into similarly digested pDB4081, encoding wild type HSA (as described above).

TABLE 7 Plasmid and amino acid substitution and relevant primers Variant Oligo 1 Oligo 2 SEQ ID (SEQ ID (SEQ ID Template Plasmid Variant No. No.) No.) plasmid Name HSA D550E + 116 KBf4 KBr30 pDB4858 pDB5042 K573P (216) (217) HSA D550K + 117 KBf4 KBr30 pDB4790 pDB5043 K573P (216) (217) HSA D550L + 118 KBf4 KBr30 pDB4791 pDB5044 K573P (216) (217) HSA D550M + 119 KBf4 KBr30 pDB4792 pDB5045 K573P (216) (217) HSA D550R + 120 KBf4 KBr30 pDB4796 pDB5046 K573P (216) (217) HSA K574D + 121 KBf4 KBr21 pDB4673 pDB4997 K573P (216) (218) HSA K574F + 122 KBf4 KBr22 pDB4673 pDB4998 K573P (216) (219) HSA K574G + 123 KBf4 KBr23 pDB4673 pDB4999 K573P (216) (220) HSA K574H + 124 KBf4 KBr24 pDB4673 pDB5000 K573P (216) (221) HSA K574N + 125 KBf4 KBr25 pDB4673 pDB5001 K573P (216) (222) HSA K574S + 126 KBf4 KBr26 pDB4673 pDB5002 K573P (216) (223) HSA K574Y + 127 KBf4 KBr27 pDB4673 pDB5005 K573P (216) (224) HSA Q580K + 128 KBf4 KBr28 pDB4673 pDB5003 K573P (216) (225) HSA Q580R + 129 KBf4 KBr29 pDB4673 pDB5004 K573P (216) (226) HSA D550K + 130 KBf4 KBr31 pDB4790 pDB5027 K574H (216) (227) HSA D550K + 131 KBf4 KBr24 pDB4790 pDB5028 K574H + (216) (221) K573P HSA D550K + 132 KBf4 KBr32 pDB4790 pDB5029 Q580K (216) (228) HSA D550K + 133 KBf4 KBr28 pDB5043 pDB5030 Q580K + (216) (225) K573P HSA K574H + 134 KBf4 KBr33 pDB4808 pDB5031 Q580K (216) (229) HSA K574H + 135 KBf4 KBr34 pDB5003 pDB5032 Q580K + (216) (230) K573P

TABLE 8 PCR reaction components HF buffer (5x) 10 μl template DNA (5 ng/μl) 1 μl dNTP (10 mM) 1 μl Phusion (polymerase) 0.5 μl oligo 1 (10 μM) 1 μl dH₂O 35.5 μl oligo 2 (10 μM) 1 μl

TABLE 9 PCR reaction conditions Temperature Cycle length Number of cycles 98° C. 2 min 1 98° C. 10 sec 35 61° C. 20 sec 72° C. 30 sec 72° C. 7 min 1

TABLE 10 PCR reaction components HF buffer (5x) 20 μl template DNA (5 ng/μl) 2 μl dNTP (10 mM) 2 μl Phusion (polymerase) 1 μl oligo 1 (10 μM) 2 μl dH₂O 71 μl oligo 2 (10 μM) 2 μl

TABLE 11 PCR reaction conditions Temperature Cycle length Number of cycles 98° C. 2 min 1 98° C. 10 sec 35 61° C. 30 sec 72° C. 20 sec 72° C. 10 min 1

Preparation of expression plasmids and transformation of S. cerevisiae was performed as described in WO2012/150319 (incorporated herein by reference), employing the 24 (pDB5027-9, pDB5032 and pDB5091-92), or 48 hour stocking method (all remaining variants). The host strain for pDB4990-5, pDB4997-5004, pDB5042-5046, pDB5027-32 and pDB5091-2 was S. cerevisiae DYB7 (Payne et al (2008) Applied and Environmental Microbiology Vol 74(24): 7759-7766) with four copies of PDI integrated into the genome. The host strain for the remaining plasmids was S. cerevisiae BXP10cir⁰ as described in WO2012/150319 (incorporated herein by reference). Protein isolation and purification from shake flask was performed as described in WO2011/051489.

Example 2: SPR Analysis of Binding Affinity of WT HSA and Variants to shFcRn

SPR analyses were performed on a Biacore 3000 instrument (GE Healthcare). Immobilisation was carried out on CM5 chips coupled with His-tagged shFcRn (FcRn produced by GeneArt, Life Technologies) using GE Healthcare amine coupling chemistry as per the manufacturer's instructions. Immobilised levels of shFcRn-HIS (shFcRn with a 6-His tail on the C-terminus of beta-2-microglobulin) were 1200-2500RU and achieved by injecting 20 μg/mL shFcRn diluted using sodium acetate pH4.5 (G E Healthcare). Chip surface was left to stabilize with a constant flow (5 μL/min) of running buffer—Di-basic/Mono-basic phosphate buffer pH5.5 ((67 mM phosphate buffer, 0.15 M NaCl, 0.005% Tween 20) at pH 5.5)) at 25° C. (i.e. ambient temperature) overnight. After ligand stabilization, the chip surface was conditioned by injecting 5-12×45 μL Di-basic/Mono-basic phosphate buffer at 30 μL/min followed by HBS EP (0.01 M HEPES, 0.15 M NaCl, 3 mM EDTA, 0.005% surfactant P20) at pH 7.4 (GE Healthcare)) regeneration steps (12s) in between each injection. Surfaces were then checked for activity by injecting 3×45 μL positive control (wt HSA (SEQ ID NO: 2)) at 30 μL/min, followed by 12s regeneration pulse. Kinetic measurements were performed by injecting dilutions (100 μM-0.016 μM) of HSA and HSA variants at 30 μL/min over immobilised shFcRn, at 25° C. (i.e. ambient temperature). The reference cell value was then subtracted and Biaevaluation software 4.1 used to obtain kinetic data and confirm KD values. The variants were wild-type albumin (SEQ ID NO: 2) and albumins with alterations at one or more of positions 492, 550, 573, 574 and 580. The variants were analysed by SPR to determine their binding response (RU) to shFcRn. Some variants were further characterized to determine KD values. The data are shown in Tables 12 to 18.

TABLE 12 Binding affinity of selected albumin variants (with a single alteration) to shFcRn % increase in Binding binding affinity Run Analyte SEQ ID No. response (RU) compared to WT A WT HSA 2 157 — HSA-K573P 3 247 57.3 HSA-E492D 34 192 22.5 HSA-E492F 35 200 27.6 HSA-E492G 36 187 19.4 HSA-E492H 37 186 18.8 HSA-E492M 41 184 17.5 HSA-E492R 45 184 17.5 B WT HSA 2 150 — HSA-K573P 3 211 40.7 HSA-D550E 53 175 16.8 HSA-D550K 58 186 24.4 HSA-D550L 59 187 24.6 HSA-D550M 60 177 18.0 HSA-D550R 64 177 18.2 C WT HSA 2 171 — HSA-K573P 3 223 30.4 HSA-K574D 72 214 25.4 HSA-K474F 74 219 27.1 HSA-K574G 75 225 31.7 HSA-K574H 76 230 34.7 HSA-K574N 80 205 20.4 HSA-K574S 84 205 20.1 HSA-K574Y 87 207 21.1 D WT HSA 2 159 — HSA-K573P 3 227 42.8 HSA-Q580K 97 212 33.4 HSA-Q580R 102 195 22.3

The data in Table 12 show that variants comprising an alteration at one of positions 492, 550, 574 and 580 show a higher FcRn binding affinity than WT albumin.

TABLE 13 Binding affinity of albumin variants (with two alterations) to shFcRn % increase in Binding binding affinity Analyte SEQ ID No. response (RU) compared to WT WT HSA 2 242.3 — HSA-K573P 3 278.0 14.7 HSA-E492D + K573P 108 270.8 11.8 HSA-E492F + K573P 109 270.3 11.6 HSA-E492G + K573P 110 275.7 13.8

The data in Table 13 show that variants comprising alterations at position 492 in conjunction with the K573P variant show higher binding affinity than WT albumin.

TABLE 14 Binding affinity of albumin variants to shFcRn Mean SEQ Ka Kd KD KD Fold difference Analyte ID NO: (10³/Ms) (10⁻³/s) (μM) (μM) from HSA-WT WT HSA (run 1) 2 10.9 40 3.67 4.02 — WT HSA (run 2) 2 9.15 39.9 4.36 HSA-K573P (run 1) 3 5.99 2.15 0.358 0.39 10.3 HSA-K573P (run 2) 3 5.95 2.53 0.426 HSA-E492D + K573P (run 1) 108 11.5 1.68 0.147 0.162 24.8 HSA-E492D + K573P (run 2) 108 11.1 1.96 0.177 HSA-E492G + K573P (run 1) 110 12.7 2.15 0.17 0.175 23.0 HSA-E492G + K573P (run 2) 110 11.3 2.04 0.18

Variants HSA-E492D+K573P and HSA-E492G+K573P were selected for further analysis based on their apparent slow ‘off rates’ (i.e. dissociation constants (Kd)). The data in Table 14 show that variants HSA-E492D+K573P and HSA-E492G+K573P show higher affinity for shFcRn as compared to WT albumin and the single K573P variant.

TABLE 15 Binding affinity of albumin variants (with two alterations) to shFcRn % increase in Binding binding affinity Analyte SEQ ID No. response (RU) compared to WT WT HSA 2 40.7 — HSA-K573P 3 55.3 35.9 HSA-K574D + K573P 121 47.2 16.0 HSA-K574F + K573P 122 49.2 20.9 HSA-K574G + K573P 123 52.1 28.0 HSA-K574H + K573P 124 53.4 31.2 HSA-K574N + K573P 125 38.4 −5.7 HSA-K574S + K573P 126 40.8 0.2 HSA-Q580K + K573P 128 53.7 31.9 HSA-Q580R + K573P 129 29.3 −28.0

The data in Table 15 show that introduction of substitutions to the K573P variant which had individually demonstrated an improvement in affinity for shFcRn (Table 12), produced a range of binding responses, from a reduction in affinity as compared to WT albumin, through to variants showing increased affinity.

TABLE 16 Binding affinity of albumin variants to shFcRn Mean SEQ Ka Kd KD KD Fold difference Analyte ID NO: (10³/Ms) (10⁻³/s) (μM) (μM) from WT HSA WT HSA 2 17.3 63.0 3.6 3.6 — HSA-K573P (run 1) 3 8.1 3.4 0.42 0.46 7.8 HSA-K573P (run 2) 3 8.0 4.0 0.5 HSA-E492H + K573P (run 1) 111 11.2 3.7 0.33 0.37 9.7 HSA-E492H + K573P (run 2) 111 11.4 4.7 0.41 HSA-E492R + K573P 113 10.3 4.3 0.42 0.42 8.6 HSA-K574G + K573P (run 1) 123 11.5 5.5 0.48 0.53 6.8 HSA-K574G + K573P (run 2) 123 11.7 6.8 0.58 HSA-K574H + K573P (run 1) 124 12.6 2.7 0.22 0.25 14.4 HSA-K574H + K573P (run 2) 124 10.8 3.08 0.29 HSA-Q580K + K573P (run 1) 128 13.4 1.9 0.14 0.15 24.0 HSA-Q580K + K573P (run 2) 128 13.2 2.19 0.16

The data in Table 16 show that variants HSA-K574H+K573P and HSA-Q580K+K573P possess considerably higher affinity for shFcRn as compared to WT albumin and the single K573P variant.

TABLE 17 Binding affinity of albumin variants to shFcRn Mean SEQ Ka Kd KD KD Fold difference Analyte ID NO: (10³/MS) (10³/s) (μM) (μM) from WT HSA WT HSA 2 9.7 72.2 7.4 6.9 — 8.9 57.3 6.4 HSA-K573P 3 6.1 3.9 0.64 0.7 9.9 5.4 4.1 0.76 HSA-D550K + K573P 117 7.1 2.8 0.4 0.5 13.8 5.6 3.3 0.6 HSA-D550K + K574H 130 10.1 36.6 3.6 3.75 1.8 8.8 34.8 3.9 HSA-D550K + Q580K 132 12.9 22.6 1.7 1.6 4.3 11.9 18.5 1.5 HSA-D550K + 131 6.5 1.6 0.25 0.31 22.3 K574H + K573P 6.2 2.4 0.38 HSA-K574H + 135 7.5 1.9 0.26 0.28 24.6 Q580K + K573P 6.0 1.8 0.3

The data in Table 17 show varying effects of the introduction of mutations at positions 550, 573, 574 and 580. For example, HSA-K574H+K573P showed increased binding compared to WT albumin (Table 16). Introduction of the K574H mutation into HSA-Q580K+K573P (Table 16) to produce HSA-K574H+Q580K+K573P resulted in no improvement in binding affinity (compared to WT albumin) over HSA-Q580K+K573P. In contrast, introduction of this mutation into HSA-D550K+K573P, producing HSA-D550K+K574H+K573P, has resulted in an increase in affinity compared to WT albumin and HSA-D550K+K573P.

TABLE 18 Binding affinity of albumin variants to shFcRn Mean SEQ Ka Kd KD KD Fold difference Analyte ID NO: Run Cycle (10³/MS) (10³/s) (μM) (μM) from WT HSA WT HSA 2 1 1 11.1 68.1 6.1 7.10 — 2 1 11.2 89.3 8.0 2 12.5 90.8 7.2 HSA-K573P 3 1 1 6.0 3.8 0.64 0.86 8.3 2 1 5.0 5.3 1.1 2 5.4 4.5 0.83 E492D + K573P + 114 1 1 7.8 1.3 0.16 0.18 39.4 K574H + Q580K 2 1 7.3 1.6 0.21 2 7.9 1.3 0.16 E492G + K573P + 115 1 1 7.8 1.3 0.16 0.22 32.3 K574H + Q580K 2 1 7.0 1.7 0.25 2 5.3 1.3 0.24

The data in Table 18 show that variants containing four substitutions at positions 492 573P, 574 and 580 show a marked increase in binding affinity as compared to variants containing three mutations, such as HSA-K574H+Q580K+K573P (Table 17), variants containing two mutations, such as K574H+K573P and Q580K+K573P (Table 16) and the single K573P variant or WT albumin.

Example 3: Production of Further Combination Variants

Single or multiple further mutations were introduced into the template plasmids listed in Table 19 to produce the indicated variants. Mutagenic forward primers and non-mutagenic reverse primers were used to introduce the desired changes, as listed in Table 20. The template plasmids were methylated using the components described in Table 21, incubated at 37° C. for one hour and were then purified using a Qiagen QiaQuick PCR purification kit according to manufacturer's instructions. The methylated template was then used in mutagenic PCR reactions (Tables 22 and 23) according to the oligonucleotide/template combination detailed in Table 19 to produce the required HSA variants. Following PCR reaction, 5 μl of each PCR reaction mixture was visualised by agarose gel electrophoresis to assess production of the plasmid and 5 μl of plasmid was retained for further analysis.

TABLE 19 Variants and associated templates and oligonucleotides for mutagenic PCR amplification Oligo Oligo Seq Variant forward reverse Template ID no. HSA E492D + D550K 01-f 01-r pDB4770 231 HSA E492D + K574H 02-f 02-r pDB4770 232 HSA E492D + K573P + 04-f 04-r pDB4770 233 K574H HSA E492D + K573P + 05-f 05-r pDB4770 234 Q580K HSA E492D + K573P + 06-f 06-r pDB4770 235 K574G + Q580K HSA E492D + K573P + 07-f 07-r pDB4770 236 K574H + Q580R HSA E492F + K573P + 08-f 08-r pDB4771 237 K574H + Q580K HSA E492F + K573P + 06-f 06-r pDB4771 238 K574G + Q580K HSA E492F + K573P + 07-f 07-r pDB4771 239 K574H + Q580R HSA E492G + D550K 01-f 01-r pDB4772 240 HSA E492G + K574H 02-f 02-r pDB4772 241 HSA E492G + K573P + 05-f 05-r pDB4772 242 Q580K HSA E492G + K573P + 06-f 06-r pDB4772 243 K574G + Q580K HSA E492G + K573P + 07-f 07-r pDB4772 244 K574H + Q580R HSA D550L + K574H 02-f 02-r pDB4791 245 HSA D550L + K573P + 04-f 04-r pDB4791 246 K574H HSA D550L + Q580K 03-f 03-r pDB4791 247 HSA D550L + K573P + 05-f 05-r pDB4791 248 Q580K HSA D550M + K574H 02-f 02-r pDB4792 249 HSA D550M + K573P + 04-f 04-r pDB4792 250 K574H HSA D550M + Q580K 03-f 03-r pDB4792 251 HSA D550M + K573P + 05-f 05-r pDB4792 252 Q580K HSA E492D + D550K + 01-f 01-r pDB4990 253 K573P HSA E492G + D550K + 01-f 01-r pDB4992 254 K573P HSA E492G + D550K + 29-f 29-r pDB5027 255 K574H HSA E492D + D550K + 28-f 28-r pDB5028 256 K573P + K574H HSA E492G + D550K + 29-f 29-r pDB5028 257 K573P + K574H HSA E492D + D550K + 28-f 28-r pDB5029 258 Q580K HSA E492G + D550K + 29-f 29-r pDB5029 259 Q580K HSA E492D + D550K + 28-f 28-r pDB5030 260 K573P + Q580K HSA E492G + D550K + 29-f 29-r pDB5030 261 K573P + Q580K HSA E492D + K574H + 28-f 28-r pDB5031 262 Q580K HSA E492G + K574H + 29-f 29-r pDB5031 263 Q580K HSA E492D + K573P + 28-f 28-r pDB5032 264 K574H + Q580K HSA D550K + K573P + 01-f 01-r pDB5032 265 K574H + Q580K HSA E492D + D550K + 01-f 01-r pDB5091 266 K573P + K574H + Q580K HSA E492G + D550K + 01-f 01-r pDB5092 267 K573P + K574H + Q580K (f = forward, r = reverse)

TABLE 20 Oligonucleotides for mutagenic PCR amplification. SEQ ID Oligo Sequence (5′ to 3′) No. 01-f GAACAATTGAAGGCTGTCATGGATAAGTTCGCTGCT 268 TTCGTTGAAAAG 01-r ATCCATGACAGCCTTCAATTGTTCCTTAGTAGCCTT 269 02-f CTTGTTTCGCTGAAGAAGGTAAGCACTTGGTCGCTG 270 CTTCCCAA 02-r CTTACCTTCTTCAGCGAAACAAGTTTCCTTATCATC 271 03-f TAAGAAGTTGGTCGCTGCTTCCAAGGCTGCCTTAGG 272 TTTGTAATAA 03-r GGAAGCAGCGACCAACTTCTTACCTTCTTCAGC 273 04-f GAAACTTGTTTCGCTGAAGAAGGTCCACACTTGGTC 274 GCTGCTTCCCAA 04-r ACCTTCTTCAGCGAAACAAGTTTCCTTATCATCAGC 275 05-f GAAACTTGTTTCGCTGAAGAAGGTCCAAAGTTGGTC 276 GCTGCTTCCAAGGCTGCCTTAGGTTTGTAA 05-r ACCTTCTTCAGCGAAACAAGTTTCCTTATCATCAGC 277 06-f GAAACTTGTTTCGCTGAAGAAGGTCCAGGTTTGGTC 278 GCTGCTTCCAAGGCTGCCTTAGGTTTGTAA 06-r ACCTTCTTCAGCGAAACAAGTTTCCTTATCATCAGC 279 07-f GAAACTTGTTTCGCTGAAGAAGGTCCACACTTGGTC 280 GCTGCTTCCAGAGCTGCCTTAGGTTTGTAA 07-r ACCTTCTTCAGCGAAACAAGTTTCCTTATCATCAGC 281 08-f GAAACTTGTTTCGCTGAAGAAGGTCCACACTTGGTC 282 GCTGCTTCCAAGGCTGCCTTAGGTTTGTAA 08-r ACCTTCTTCAGCGAAACAAGTTTCCTTATCATCAGC 283 28-f GAAGACCATGTTTCTCTGCTTTGGACGTCGACGAAA 284 CTTACGTTC 28-r CAAAGCAGAGAAACATGGTCTTCTGTTAACCAAAGA 285 29-f GAAGACCATGTTTCTCTGCTTTGGGTGTCGACGAAA 286 CTTACGTTC 29-r CAAAGCAGAGAAACATGGTCTTCTGTTAACCAAAGA 287 (f = forward, r = reverse)

TABLE 21 Methylation reaction components Template DNA 2.5 μg 10X Buffer (New England Biolabs) 5 μl Dam methylase (New England Biolabs) 1 μl S adenosylmethionine (80 μM) (New England Biolabs) 12.5 μl H₂O Up to 50 μl

TABLE 22 PCR reaction components Template (5 ng/μl) 1 μl Forward primer (20 μM) 1.25 μl 5x buffer 10 μl Reverse primer (20 μM) 1.25 μl dNTP (10 mM) 1 μl Q5 polymerase 0.5 μl Sterile water 35

TABLE 23 PCR reaction conditions for construction of variants listed in Table 19 Temperature Cycle Length Number of cycles 98° C. 2 min 1 98° C. 10 sec 30 65° C.*/60° C.^(#) 30 sec 72° C. 5 min 72° C. 7 min 1

40 μl of each of the PCR-generated plasmids was prepared for in vivo recombination by the addition of 0.5 μl of each of DpnI, NsiI and PvuI restriction enzymes (New England Biolabs), followed by incubation at 37° C. for one hour. 3 μl of the prepared plasmid, 3 μl of Acc65I/BamHI-digested pDB3936 and 1 μl of salmon sperm DNA were used to transform S. cerevisiae according to the protocol described in Example 1. The host strain used was a S. cerevisiae strain derived from DYB7 ura3 (Payne et al 2008, Appl. Environ. Microbiol. 74(24): 7759-7766) with two additional copies of PDI1 integrated into the genome. Single colonies were patched onto BMMD+CSM-leu plates (as described in WO 2012/150319, incorporated herein by reference) to enable assessment of expression prior to production of yeast stocks. Stocks were produced by the 48-hour method described in Example 1. 200 μl of each yeast strain was used to inoculate 10 ml BMMS in 50 ml shake flask, followed by incubation at 30° C., 200 rpm for four days. Culture supernatant was harvested by centrifugation at 3000 rpm for 5 minutes.

Albumin variants were purified from 10 mL shake flasks using a single chromatographic step with an albumin affinity matrix (AlbuPure™—ProMetic BioSciences, Inc.). Micro-scale affinity chromatography was performed on an automated platform (Perkin Elmer, Janus) with 2004, custom packed Atoll columns with 8 run in parallel in a 96-well format using the same procedure as described in WO 2011/051489 (incorporated herein by reference), with volumes scaled down appropriately.

Final concentration of the samples was determined by Absorbance at 280 nm using a UV microplate and a plate reader, readings were blank corrected against PBS and the concentrations calculated based on an extinction coefficient of 0.52 AU/cm for a 1 mg/mL solution (AU: absorbance units).

Example 4: Analysis of Further Combination Variants

Kinetic analyses using bio-layer interferometry were performed on an Octet Red-96 instrument (ForteBio). Immobilisation of GST-tagged shFcRn (shFcRn-GST/FLAG) was carried out on AR2G biosensors using ForteBio amine coupling chemistry following the instructions from the manufacturer. shFcRn-GST/FLAG- refers to GST-tag (glutathione-transferase) and a FLAG-tag (DYKDDDDK) on the C-terminal of the alpha chain of FcRn. Prior to use, the GST/FLAG-tagged shFcRn was purified using IgG affinity chromatography. More specifically, the GST/FLAG-tagged shFcRn was captured on a GSTrap column and eluted with reduced glutathione. shFcRn was dialyzed into PBS into pH 7.4 and further purified using IgG Sepharose™ 6 Fast Flow (GE Healthcare). The shFcRn was captured on the resin in 50 mM Na-acetate, 150 mM NaCl pH 5.5 and eluted with PBS pH 7.4. The eluted shFcRn was concentrated to 2-5 mg/mL and stored at −20° C. until use. Immobilised level of shFcRn-GST/FLAG was at a response level more than 1 nm, and achieved using a FcRn concentration of 2-10 μg/mL in sodium acetate, followed by ethanolamine quenching of the amine coupling reaction. The sensors were either used directly or soaked in 15% (w/v) sucrose and dried until use.

Kinetic analyses were performed using micro-scale affinity purified albumin variants diluted 2-, 4- and 8-fold in BMMD fermentation media (as described WO 2011/051489, incorporated herein by reference) supplemented with 100 mM sodium acetate and adjusted to pH 5.5. Association (120s) and dissociation (300s) were performed at 30° C. and shaking at 1000 rpm. ForteBio software was used for data evaluation and calculation of KD values as well as association and dissociation constants which were calculated using the HSA concentrations determined by OD280 nm measurement.

TABLE 24 Binding affinity of albumin variants to shFcRn Fold difference SEQ KD Average relative to ID No: Variant μM WT HSA 231 HSA E492D + D550K 0.12 1.2 232 HSA E492D + K574H 0.14 1.1 233 HSA E492D + K573P + 0.04 3.8 K574H 234 HSA E492D + K573P + 0.03 5.8 Q580K 235 HSA E492D + K573P + 0.04 3.9 K574G + Q580K 236 HSA E492D + K573P + 0.03 5.5 K574H + Q580R 237 HSA E492F + K573P + 0.03 6.0 K574H + Q580K 238 HSA E492F + K573P + 0.06 2.6 K574G + Q580K 239 HSA E492F + K573P + 0.03 4.5 K574H + Q580R 240 HSA E492G + D550K 0.13 1.2 241 HSA E492G + K574H 0.14 1.1 242 HSA E492G + K573P + 0.03 5.8 Q580K 243 HSA E492G + K573P + 0.04 3.9 K574G + Q580K 244 HSA E492G + K573P + 0.03 5.5 K574H + Q580R 245 HSA D550L + K574H 0.06 2.4 246 HSA D550L + K573P + 0.04 4.2 K574H 247 HSA D550L + Q580K 0.10 1.5 248 HSA D550L + K573P + 0.03 5.9 Q580K 249 HSA D550M + K574H 0.13 1.2 250 HSA D550M + K573P + 0.03 5.0 K574H 251 HSA D550M + Q580K 0.10 1.5 252 HSA D550M + K573P + 0.02 7.2 Q580K 253 HSA E492D + D550K + 0.03 4.8 K573P 254 HSA E492G + D550K + 0.03 4.5 K573P 255 HSA E492G + D550K + 0.12 1.3 K574H 256 HSA E492D + D550K + 0.03 4.6 K573P + K574H 258 HSA E492D + D550K + 0.09 1.7 Q580K 259 HSA E492G + D550K + 0.08 1.8 Q580K 260 HSA E492D + D550K + 0.03 5.2 K573P + Q580K 261 HSA E492G + D550K + 0.02 6.1 K573P + Q580K 262 HSA E492D + K574H + 0.11 1.4 Q580K 263 HSA E492G + K574H + 0.08 1.9 Q580K 264 HSA E492D + K573P + 0.03 5.3 K574H + Q580K 265 HSA D550K + K573P + 0.02 6.1 K574H + Q580K 266 HSA E492D + D550K + 0.02 6.5 K573P + K574H + Q580K 267 HSA E492G + D550K + 0.02 6.9 K573P + K574H + Q580K 2 WT HSA 0.15 1.0

Example 5: Further Analysis of Selected Combination Variants

A subset of the variants (Table 25) described in Table 19 were selected for further analysis. 3 μl of the PCR reactions were digested with 7 μl of a reaction mix containing 10 μl of buffer 4 (New England Biolabs), 5 μl DpnI and 55 μl of water. Reaction mixtures were incubated at 37° C. for 1.5 hours and were then purified using a Qiagen QiaQuick PCR purification kit according to manufacturer's instructions. 2 μl of the prepared plasmids were used to transform competent E. coli 10-beta cells (New England Biolabs). Plasmid DNA was prepared utilising a Qiagen Plus Maxiprep kit, according to manufacturer's instructions. The resulting plasmids were sequenced to ensure the desired mutations had been introduced. Plasmid preparation and yeast transformations were performed as described in example 1, using strain BXP10 cir⁰. 24 hour yeast stocks were produced as described in example 1.

TABLE 25 Variant and plasmid number SEQ Variant Plasmid Construct ID No HSA E492D + K574H pDB5386 HSAE-2 232 HSA E492D + K573P + pDB5387 HSAE-5 234 Q580K HSA D550L + K573P + pDB5388 HSAE-19 246 K574H HSA D550L + K573P + pDB5389 HSAE-21 248 Q580K HSA D550M + Q580K pDB5390 HSAE-24 251 HSA E492D + D550K + pDB5391 HSAE-26 253 K573P HSA E492G + D550K + pDB5392 HSAE-27 254 K573P HSA E492G + D550K + pDB5393 HSAE-31 257 K573P + K574H

The variants listed in Table 26 and 27 were analyzed by SPR using a Biacore 3000 instrument as described in Example 2 with the exception that, prior to use, the His-tagged shFcRn was purified using IgG affinity chromatography. More specifically, the His-tagged shFcRn was captured on a Ni-HiTrap column and eluted with imidazole. The shFcRn was captured on the resin in 50 mM Na-acetate, 150 mM NaCl pH 5.5 and eluted with PBS pH 7.4. The eluted shFcRn was concentrated to 2-5 mg/mL and stored at −20° C. until use. using shFcRn-HIS

TABLE 26 SPR analysis of binding affinity of HSA variants to shFcRn Fold difference SEQ Ka Kd KD relative to Variant ID No (10³/Ms) (10⁻³/s) μM WT HSA HSA WT 2 10.2 76.3 7.5 — HSA K573P 3 11.2 7.1 0.63 11.9 HSA E492D + 232 17.5 48.7 2.8 2.7 K574H HSA E492D + 234 19.5 2.2 0.11 68.2 K573P + Q580K HSA D550L + 246 15.6 3.6 0.23 32.6 K573P + K574H HSA D550M + 251 21.1 28.2 1.3 5.8 Q580K HSA E492D + 253 17.6 3.2 0.18 41.7 D550K + K573P HSA E492G + 254 20.0 3.2 0.16 46.9 D550K + K573P HSA E492G + 257 17.0 2.6 0.15 50 D550K + K573P + K574H HSA D550L + 248 18.0 1.7 0.09 83.3 K573P + Q580K

TABLE 27 SPR analysis of binding affinity of HSA variants to shFcRn Fold difference SEQ Ka Kd KD relative to Variant ID No (10³/Ms) (10⁻³/s) μM WT HSA HSA WT 2 16.7 101 6.1 — HSA K573P 3 16.4 9.75 0.6 10.2 HSA D550K + 131 27.5 4.4 0.16 38.1 K573P + K574H HSA K573P + 135 24.7 3.2 0.13 46.9 K574H + Q580K HSA D550K + 133 44.2 1.9 0.05 122 K573P + Q580K HSA D550L + 248 36.3 2.12 0.06 101.7 K573P + Q580K

The data of Table 26 and 27 show an improvement in affinity over WT HSA in variants containing a combination of substitutions. Generally, variants containing three or four substitutions show improved binding characteristics over those containing two substitutions. Generally, inclusion of Q580K contributes substantially to an improved binding affinity.

The invention described and claimed herein is not to be limited in scope by the specific aspects herein disclosed, since these aspects are intended as illustrations of several aspects of the invention. Any equivalent aspects are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure including definitions will control. 

1. (canceled)
 2. A polypeptide which is a variant of albumin, a fragment thereof or a fusion polypeptide comprising said variant albumin or a fragment thereof, having an increased binding affinity to FcRn as compared with the FcRn binding affinity of a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof, wherein the polypeptide comprises: a substitution to P, Y, W, H, F, T, I or V at a position corresponding to position 573 of SEQ ID NO: 2; a substitution to H, D, F, G, N, S or Y at a position corresponding to position 574 of SEQ ID NO: 2; and a substitution to K or R at a position corresponding to position 580 of SEQ ID NO: 2, wherein said polypeptide has a stronger binding affinity to FcRn or a longer plasma half-life than a parent albumin, reference albumin or fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof.
 3. The polypeptide according to claim 2, further comprising a substitution to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W or Y at a position corresponding to position 492 of SEQ ID NO:
 2. 4. The polypeptide according to claim 2, further comprising a substitution to A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W or Y at a position corresponding to position 550 of SEQ ID NO:
 2. 5. The polypeptide according to claim 2, comprising alterations corresponding to the following positions in SEQ ID NO: 2: 492G+573P+574H+580K, as set forth in SEQ ID NO: 115; 492G+550K+573P+574H, as set forth in SEQ ID NO: 257; 492D+550K+573P+574H, as set forth in SEQ ID NO: 256; 492G+550K+573P, as set forth in SEQ ID NO: 254; 492D+550K+573P, as set forth in SEQ ID NO: 253; 550M+573P+580K, as set forth in SEQ ID NO: 252; 550L+573P+580K, as set forth in SEQ ID NO: 248; 550L+573P+574H, as set forth in SEQ ID NO: 246; 492G+573P+580K, as set forth in SEQ ID NO: 242; 492D+573P+580K, as set forth in SEQ ID NO: 234; 573P+574H+580K, as set forth in SEQ ID NO: 135; 550K+573P+580K, as set forth in SEQ ID NO: 133; 550K+573P+574H, as set forth in SEQ ID NO: 131; or 492D+573P+574H+580K, as set forth in SEQ ID NO:
 114. 6. The polypeptide according to claim 5, comprising 492D+573P+574H+580K, as set forth in SEQ ID NO:
 114. 7. The polypeptide according to claim 5, comprising 492G+573P+574H+580K, as set forth in SEQ ID NO:
 115. 8. The polypeptide according to claim 2, wherein the reference albumin is HSA (SEQ ID NO: 2) or a fragment thereof, or a fusion polypeptide comprising HSA or a fragment thereof.
 9. The polypeptide of claim 2, wherein the sequence identity of said polypeptide to SEQ ID NO: 2 is more than 80%, more than 90%, more than 95%, more than 96%, more than 97%, more than 98% or more than 99%.
 10. The polypeptide of claim 2, wherein said fusion comprises a fusion partner polypeptide selected from a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.
 11. The polypeptide of claim 2, wherein said polypeptide further comprises a non-albumin moiety covalently attached to said polypeptide.
 12. The polypeptide of claim 2, wherein said polypeptide further comprises a non-albumin moiety noncovalently associated with said polypeptide.
 13. A conjugate comprising a polypeptide according to claim 2 and a conjugation partner, wherein the conjugation partner is a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.
 14. An associate comprising a polypeptide according to claim 2 and a therapeutic, prophylactic, diagnostic, imaging or other beneficial moiety.
 15. A nanoparticle or microparticle comprising a polypeptide according to claim
 2. 16. A composition comprising a polypeptide according to claim
 2. 17. A nucleic acid encoding the polypeptide or fusion polypeptide of claim
 2. 18. A vector comprising a nucleic acid according to claim
 17. 19. A host cell, comprising a nucleic acid according to claim
 17. 20. A method of prophylaxis, treatment or diagnosis comprising administering a polypeptide according to claim 2 to a subject.
 21. A method of altering the binding activity of a polypeptide, which is a variant of albumin, a fragment thereof or a fusion polypeptide comprising said variant albumin or fragment thereof, to FcRn as compared with the FcRn binding activity of a parent albumin, reference albumin, fragment thereof or a fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof, comprising contacting FcRn with said polypeptide, wherein said polypeptide further comprises: a substitution to P, Y, W, H, F, T, I or V at a position corresponding to position 573 of SEQ ID NO: 2; a substitution to H, D, F, G, N, S or Y at a position corresponding to position 574 of SEQ ID NO: 2; and a substitution to K or R at a position corresponding to position 580 of SEQ ID NO: 2, wherein said polypeptide has a stronger binding affinity to FcRn or longer plasma half-life than a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof.
 22. A method for altering the circulating half-life of a molecule comprising: providing a variant of albumin, a fragment thereof or a fusion polypeptide comprising said variant albumin or fragment thereof; and a) where the molecule is a polypeptide, fusing or conjugating the molecule to said variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof; or b) where the molecule is not a polypeptide, conjugating the molecule to said variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof; or c) contacting the molecule with said variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof, wherein said contacting results in a noncovalent association between said molecule and variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof; wherein said variant of albumin, fragment thereof or fusion polypeptide comprising said variant albumin or fragment thereof comprises: a substitution to P, Y, W, H, F, T, I or V at a position corresponding to position 573 of SEQ ID NO: 2; a substitution to H, D, F, G, N, S or Y at a position corresponding to position 574 of SEQ ID NO: 2; and a substitution to K or R at a position corresponding to position 580 of SEQ ID NO: 2, wherein said polypeptide has a stronger binding affinity to FcRn or longer plasma half-life than a parent albumin, reference albumin, fragment thereof or fusion polypeptide comprising said parent albumin, reference albumin or fragment or fusion thereof. 